text: """
  Ported using Python-Future from the Python 3.3 standard library.
  
  Parse (absolute and relative) URLs.
  
  urlparse module is based upon the following RFC specifications.
  
  RFC 3986 (STD66): "Uniform Resource Identifiers" by T. Berners-Lee, R. Fielding
  and L.  Masinter, January 2005.
  
  RFC 2732 : "Format for Literal IPv6 Addresses in URL's by R.Hinden, B.Carpenter
  and L.Masinter, December 1999.
  
  RFC 2396:  "Uniform Resource Identifiers (URI)": Generic Syntax by T.
  Berners-Lee, R. Fielding, and L. Masinter, August 1998.
  
  RFC 2368: "The mailto URL scheme", by P.Hoffman , L Masinter, J. Zawinski, July 1998.
  
  RFC 1808: "Relative Uniform Resource Locators", by R. Fielding, UC Irvine, June
  1995.
  
  RFC 1738: "Uniform Resource Locators (URL)" by T. Berners-Lee, L. Masinter, M.
  McCahill, December 1994
  
  RFC 3986 is considered the current standard and any future changes to
  urlparse module should conform with it.  The urlparse module is
  currently not entirely compliant with this RFC due to defacto
  scenarios for parsing, and for backward compatibility purposes, some
  parsing quirks from older RFCs are retained. The testcases in
  test_urlparse.py provides a good indicator of parsing behavior.
  """
  from __future__ import absolute_import, division, unicode_literals
  from future.builtins import bytes, chr, dict, int, range, str
  from future.utils import raise_with_traceback
  
  import re
  import sys
  import collections
  
  __all__ = ["urlparse", "urlunparse", "urljoin", "urldefrag",
             "urlsplit", "urlunsplit", "urlencode", "parse_qs",
             "parse_qsl", "quote", "quote_plus", "quote_from_bytes",
             "unquote", "unquote_plus", "unquote_to_bytes"]
  
  # A classification of schemes ('' means apply by default)
  uses_relative = ['ftp', 'http', 'gopher', 'nntp', 'imap',
                   'wais', 'file', 'https', 'shttp', 'mms',
                   'prospero', 'rtsp', 'rtspu', '', 'sftp',
                   'svn', 'svn+ssh']
  uses_netloc = ['ftp', 'http', 'gopher', 'nntp', 'telnet',
                 'imap', 'wais', 'file', 'mms', 'https', 'shttp',
                 'snews', 'prospero', 'rtsp', 'rtspu', 'rsync', '',
                 'svn', 'svn+ssh', 'sftp', 'nfs', 'git', 'git+ssh']
  uses_params = ['ftp', 'hdl', 'prospero', 'http', 'imap',
                 'https', 'shttp', 'rtsp', 'rtspu', 'sip', 'sips',
                 'mms', '', 'sftp', 'tel']
  
  # These are not actually used anymore, but should stay for backwards
  # compatibility.  (They are undocumented, but have a public-looking name.)
  non_hierarchical = ['gopher', 'hdl', 'mailto', 'news',
                      'telnet', 'wais', 'imap', 'snews', 'sip', 'sips']
  uses_query = ['http', 'wais', 'imap', 'https', 'shttp', 'mms',
                'gopher', 'rtsp', 'rtspu', 'sip', 'sips', '']
  uses_fragment = ['ftp', 'hdl', 'http', 'gopher', 'news',
                   'nntp', 'wais', 'https', 'shttp', 'snews',
                   'file', 'prospero', '']
  
  # Characters valid in scheme names
  scheme_chars = ('abcdefghijklmnopqrstuvwxyz'
                  'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
                  '0123456789'
                  '+-.')
  
  # XXX: Consider replacing with functools.lru_cache
  MAX_CACHE_SIZE = 20
  _parse_cache = {}
  
  def clear_cache():
      """Clear the parse cache and the quoters cache."""
      _parse_cache.clear()
      _safe_quoters.clear()
  
  
  # Helpers for bytes handling
  # For 3.2, we deliberately require applications that
  # handle improperly quoted URLs to do their own
  # decoding and encoding. If valid use cases are
  # presented, we may relax this by using latin-1
  # decoding internally for 3.3
  _implicit_encoding = 'ascii'
  _implicit_errors = 'strict'
  
  def _noop(obj):
      return obj
  
  def _encode_result(obj, encoding=_implicit_encoding,
                          errors=_implicit_errors):
      return obj.encode(encoding, errors)
  
  def _decode_args(args, encoding=_implicit_encoding,
                         errors=_implicit_errors):
      return tuple(x.decode(encoding, errors) if x else '' for x in args)
  
  def _coerce_args(*args):
      # Invokes decode if necessary to create str args
      # and returns the coerced inputs along with
      # an appropriate result coercion function
      #   - noop for str inputs
      #   - encoding function otherwise
      str_input = isinstance(args[0], basestring)
      for arg in args[1:]:
          # We special-case the empty string to support the
          # "scheme=''" default argument to some functions
          if arg and isinstance(arg, basestring) != str_input:
              raise TypeError("Cannot mix str and non-str arguments")
      if str_input:
          return args + (_noop,)
      return _decode_args(args) + (_encode_result,)
  
  # Result objects are more helpful than simple tuples
  class _ResultMixinStr(object):
      """Standard approach to encoding parsed results from str to bytes"""
      __slots__ = ()
  
      def encode(self, encoding='ascii', errors='strict'):
          return self._encoded_counterpart(*(x.encode(encoding, errors) for x in self))
  
  
  class _ResultMixinBytes(object):
      """Standard approach to decoding parsed results from bytes to str"""
      __slots__ = ()
  
      def decode(self, encoding='ascii', errors='strict'):
          return self._decoded_counterpart(*(x.decode(encoding, errors) for x in self))
  
  
  class _NetlocResultMixinBase(object):
      """Shared methods for the parsed result objects containing a netloc element"""
      __slots__ = ()
  
      @property
      def username(self):
          return self._userinfo[0]
  
      @property
      def password(self):
          return self._userinfo[1]
  
      @property
      def hostname(self):
          hostname = self._hostinfo[0]
          if not hostname:
              hostname = None
          elif hostname is not None:
              hostname = hostname.lower()
          return hostname
  
      @property
      def port(self):
          port = self._hostinfo[1]
          if port is not None:
              port = int(port, 10)
              # Return None on an illegal port
              if not ( 0 <= port <= 65535):
                  return None
          return port
  
  
  class _NetlocResultMixinStr(_NetlocResultMixinBase, _ResultMixinStr):
      __slots__ = ()
  
      @property
      def _userinfo(self):
          netloc = self.netloc
          userinfo, have_info, hostinfo = netloc.rpartition('@')
          if have_info:
              username, have_password, password = userinfo.partition(':')
              if not have_password:
                  password = None
          else:
              username = password = None
          return username, password
  
      @property
      def _hostinfo(self):
          netloc = self.netloc
          _, _, hostinfo = netloc.rpartition('@')
          _, have_open_br, bracketed = hostinfo.partition('[')
          if have_open_br:
              hostname, _, port = bracketed.partition(']')
              _, have_port, port = port.partition(':')
          else:
              hostname, have_port, port = hostinfo.partition(':')
          if not have_port:
              port = None
          return hostname, port
  
  
  class _NetlocResultMixinBytes(_NetlocResultMixinBase, _ResultMixinBytes):
      __slots__ = ()
  
      @property
      def _userinfo(self):
          netloc = self.netloc
          userinfo, have_info, hostinfo = netloc.rpartition(b'@')
          if have_info:
              username, have_password, password = userinfo.partition(b':')
              if not have_password:
                  password = None
          else:
              username = password = None
          return username, password
  
      @property
      def _hostinfo(self):
          netloc = self.netloc
          _, _, hostinfo = netloc.rpartition(b'@')
          _, have_open_br, bracketed = hostinfo.partition(b'[')
          if have_open_br:
              hostname, _, port = bracketed.partition(b']')
              _, have_port, port = port.partition(b':')
          else:
              hostname, have_port, port = hostinfo.partition(b':')
          if not have_port:
              port = None
          return hostname, port
  
  
  from collections import namedtuple
  
  _DefragResultBase = namedtuple('DefragResult', 'url fragment')
  _SplitResultBase = namedtuple('SplitResult', 'scheme netloc path query fragment')
  _ParseResultBase = namedtuple('ParseResult', 'scheme netloc path params query fragment')
  
  # For backwards compatibility, alias _NetlocResultMixinStr
  # ResultBase is no longer part of the documented API, but it is
  # retained since deprecating it isn't worth the hassle
  ResultBase = _NetlocResultMixinStr
  
  # Structured result objects for string data
  class DefragResult(_DefragResultBase, _ResultMixinStr):
      __slots__ = ()
      def geturl(self):
          if self.fragment:
              return self.url + '#' + self.fragment
          else:
              return self.url
  
  class SplitResult(_SplitResultBase, _NetlocResultMixinStr):
      __slots__ = ()
      def geturl(self):
          return urlunsplit(self)
  
  class ParseResult(_ParseResultBase, _NetlocResultMixinStr):
      __slots__ = ()
      def geturl(self):
          return urlunparse(self)
  
  # Structured result objects for bytes data
  class DefragResultBytes(_DefragResultBase, _ResultMixinBytes):
      __slots__ = ()
      def geturl(self):
          if self.fragment:
              return self.url + b'#' + self.fragment
          else:
              return self.url
  
  class SplitResultBytes(_SplitResultBase, _NetlocResultMixinBytes):
      __slots__ = ()
      def geturl(self):
          return urlunsplit(self)
  
  class ParseResultBytes(_ParseResultBase, _NetlocResultMixinBytes):
      __slots__ = ()
      def geturl(self):
          return urlunparse(self)
  
  # Set up the encode/decode result pairs
  def _fix_result_transcoding():
      _result_pairs = (
          (DefragResult, DefragResultBytes),
          (SplitResult, SplitResultBytes),
          (ParseResult, ParseResultBytes),
      )
      for _decoded, _encoded in _result_pairs:
          _decoded._encoded_counterpart = _encoded
          _encoded._decoded_counterpart = _decoded
  
  _fix_result_transcoding()
  del _fix_result_transcoding
  
  def urlparse(url, scheme='', allow_fragments=True):
      """Parse a URL into 6 components:
      <scheme>://<netloc>/<path>;<params>?<query>#<fragment>
      Return a 6-tuple: (scheme, netloc, path, params, query, fragment).
      Note that we don't break the components up in smaller bits
      (e.g. netloc is a single string) and we don't expand % escapes."""
      url, scheme, _coerce_result = _coerce_args(url, scheme)
      splitresult = urlsplit(url, scheme, allow_fragments)
      scheme, netloc, url, query, fragment = splitresult
      if scheme in uses_params and ';' in url:
          url, params = _splitparams(url)
      else:
          params = ''
      result = ParseResult(scheme, netloc, url, params, query, fragment)
      return _coerce_result(result)
  
  def _splitparams(url):
      if '/'  in url:
          i = url.find(';', url.rfind('/'))
          if i < 0:
              return url, ''
      else:
          i = url.find(';')
      return url[:i], url[i+1:]
  
  def _splitnetloc(url, start=0):
      delim = len(url)   # position of end of domain part of url, default is end
      for c in '/?#':    # look for delimiters; the order is NOT important
          wdelim = url.find(c, start)        # find first of this delim
          if wdelim >= 0:                    # if found
              delim = min(delim, wdelim)     # use earliest delim position
      return url[start:delim], url[delim:]   # return (domain, rest)
  
  def urlsplit(url, scheme='', allow_fragments=True):
      """Parse a URL into 5 components:
      <scheme>://<netloc>/<path>?<query>#<fragment>
      Return a 5-tuple: (scheme, netloc, path, query, fragment).
      Note that we don't break the components up in smaller bits
      (e.g. netloc is a single string) and we don't expand % escapes."""
      url, scheme, _coerce_result = _coerce_args(url, scheme)
      allow_fragments = bool(allow_fragments)
      key = url, scheme, allow_fragments, type(url), type(scheme)
      cached = _parse_cache.get(key, None)
      if cached:
          return _coerce_result(cached)
      if len(_parse_cache) >= MAX_CACHE_SIZE: # avoid runaway growth
          clear_cache()
      netloc = query = fragment = ''
      i = url.find(':')
      if i > 0:
          if url[:i] == 'http': # optimize the common case
              scheme = url[:i].lower()
              url = url[i+1:]
              if url[:2] == '//':
                  netloc, url = _splitnetloc(url, 2)
                  if (('[' in netloc and ']' not in netloc) or
                          (']' in netloc and '[' not in netloc)):
                      raise ValueError("Invalid IPv6 URL")
              if allow_fragments and '#' in url:
                  url, fragment = url.split('#', 1)
              if '?' in url:
                  url, query = url.split('?', 1)
              v = SplitResult(scheme, netloc, url, query, fragment)
              _parse_cache[key] = v
              return _coerce_result(v)
          for c in url[:i]:
              if c not in scheme_chars:
                  break
          else:
              # make sure "url" is not actually a port number (in which case
              # "scheme" is really part of the path)
              rest = url[i+1:]
              if not rest or any(c not in '0123456789' for c in rest):
                  # not a port number
                  scheme, url = url[:i].lower(), rest
  
      if url[:2] == '//':
          netloc, url = _splitnetloc(url, 2)
          if (('[' in netloc and ']' not in netloc) or
                  (']' in netloc and '[' not in netloc)):
              raise ValueError("Invalid IPv6 URL")
      if allow_fragments and '#' in url:
          url, fragment = url.split('#', 1)
      if '?' in url:
          url, query = url.split('?', 1)
      v = SplitResult(scheme, netloc, url, query, fragment)
      _parse_cache[key] = v
      return _coerce_result(v)
  
  def urlunparse(components):
      """Put a parsed URL back together again.  This may result in a
      slightly different, but equivalent URL, if the URL that was parsed
      originally had redundant delimiters, e.g. a ? with an empty query
      (the draft states that these are equivalent)."""
      scheme, netloc, url, params, query, fragment, _coerce_result = (
                                                    _coerce_args(*components))
      if params:
          url = "%s;%s" % (url, params)
      return _coerce_result(urlunsplit((scheme, netloc, url, query, fragment)))
  
  def urlunsplit(components):
      """Combine the elements of a tuple as returned by urlsplit() into a
      complete URL as a string. The data argument can be any five-item iterable.
      This may result in a slightly different, but equivalent URL, if the URL that
      was parsed originally had unnecessary delimiters (for example, a ? with an
      empty query; the RFC states that these are equivalent)."""
      scheme, netloc, url, query, fragment, _coerce_result = (
                                            _coerce_args(*components))
      if netloc or (scheme and scheme in uses_netloc and url[:2] != '//'):
          if url and url[:1] != '/': url = '/' + url
          url = '//' + (netloc or '') + url
      if scheme:
          url = scheme + ':' + url
      if query:
          url = url + '?' + query
      if fragment:
          url = url + '#' + fragment
      return _coerce_result(url)
  
  def urljoin(base, url, allow_fragments=True):
      """Join a base URL and a possibly relative URL to form an absolute
      interpretation of the latter."""
      if not base:
          return url
      if not url:
          return base
      base, url, _coerce_result = _coerce_args(base, url)
      bscheme, bnetloc, bpath, bparams, bquery, bfragment = \
              urlparse(base, '', allow_fragments)
      scheme, netloc, path, params, query, fragment = \
              urlparse(url, bscheme, allow_fragments)
      if scheme != bscheme or scheme not in uses_relative:
          return _coerce_result(url)
      if scheme in uses_netloc:
          if netloc:
              return _coerce_result(urlunparse((scheme, netloc, path,
                                                params, query, fragment)))
          netloc = bnetloc
      if path[:1] == '/':
          return _coerce_result(urlunparse((scheme, netloc, path,
                                            params, query, fragment)))
      if not path and not params:
          path = bpath
          params = bparams
          if not query:
              query = bquery
          return _coerce_result(urlunparse((scheme, netloc, path,
                                            params, query, fragment)))
      segments = bpath.split('/')[:-1] + path.split('/')
      # XXX The stuff below is bogus in various ways...
      if segments[-1] == '.':
          segments[-1] = ''
      while '.' in segments:
          segments.remove('.')
      while 1:
          i = 1
          n = len(segments) - 1
          while i < n:
              if (segments[i] == '..'
                  and segments[i-1] not in ('', '..')):
                  del segments[i-1:i+1]
                  break
              i = i+1
          else:
              break
      if segments == ['', '..']:
          segments[-1] = ''
      elif len(segments) >= 2 and segments[-1] == '..':
          segments[-2:] = ['']
      return _coerce_result(urlunparse((scheme, netloc, '/'.join(segments),
                                        params, query, fragment)))
  
  def urldefrag(url):
      """Removes any existing fragment from URL.
  
      Returns a tuple of the defragmented URL and the fragment.  If
      the URL contained no fragments, the second element is the
      empty string.
      """
      url, _coerce_result = _coerce_args(url)
      if '#' in url:
          s, n, p, a, q, frag = urlparse(url)
          defrag = urlunparse((s, n, p, a, q, ''))
      else:
          frag = ''
          defrag = url
      return _coerce_result(DefragResult(defrag, frag))
  
  _hexdig = '0123456789ABCDEFabcdef'
  _hextobyte = dict(((a + b).encode(), bytes([int(a + b, 16)]))
                    for a in _hexdig for b in _hexdig)
  
  def unquote_to_bytes(string):
      """unquote_to_bytes('abc%20def') -> b'abc def'."""
      # Note: strings are encoded as UTF-8. This is only an issue if it contains
      # unescaped non-ASCII characters, which URIs should not.
      if not string:
          # Is it a string-like object?
          string.split
          return bytes(b'')
      if isinstance(string, str):
          string = string.encode('utf-8')
      ### For Python-Future:
      # It is already a byte-string object, but force it to be newbytes here on
      # Py2:
      string = bytes(string)
      ###
      bits = string.split(b'%')
      if len(bits) == 1:
          return string
      res = [bits[0]]
      append = res.append
      for item in bits[1:]:
          try:
              append(_hextobyte[item[:2]])
              append(item[2:])
          except KeyError:
              append(b'%')
              append(item)
      return bytes(b'').join(res)
  
  _asciire = re.compile('([\x00-\x7f]+)')
  
  def unquote(string, encoding='utf-8', errors='replace'):
      """Replace %xx escapes by their single-character equivalent. The optional
      encoding and errors parameters specify how to decode percent-encoded
      sequences into Unicode characters, as accepted by the bytes.decode()
      method.
      By default, percent-encoded sequences are decoded with UTF-8, and invalid
      sequences are replaced by a placeholder character.
  
      unquote('abc%20def') -> 'abc def'.
      """
      if '%' not in string:
          string.split
          return string
      if encoding is None:
          encoding = 'utf-8'
      if errors is None:
          errors = 'replace'
      bits = _asciire.split(string)
      res = [bits[0]]
      append = res.append
      for i in range(1, len(bits), 2):
          append(unquote_to_bytes(bits[i]).decode(encoding, errors))
          append(bits[i + 1])
      return ''.join(res)
  
  def parse_qs(qs, keep_blank_values=False, strict_parsing=False,
               encoding='utf-8', errors='replace'):
      """Parse a query given as a string argument.
  
          Arguments:
  
          qs: percent-encoded query string to be parsed
  
          keep_blank_values: flag indicating whether blank values in
              percent-encoded queries should be treated as blank strings.
              A true value indicates that blanks should be retained as
              blank strings.  The default false value indicates that
              blank values are to be ignored and treated as if they were
              not included.
  
          strict_parsing: flag indicating what to do with parsing errors.
              If false (the default), errors are silently ignored.
              If true, errors raise a ValueError exception.
  
          encoding and errors: specify how to decode percent-encoded sequences
              into Unicode characters, as accepted by the bytes.decode() method.
      """
      parsed_result = {}
      pairs = parse_qsl(qs, keep_blank_values, strict_parsing,
                        encoding=encoding, errors=errors)
      for name, value in pairs:
          if name in parsed_result:
              parsed_result[name].append(value)
          else:
              parsed_result[name] = [value]
      return parsed_result
  
  def parse_qsl(qs, keep_blank_values=False, strict_parsing=False,
                encoding='utf-8', errors='replace'):
      """Parse a query given as a string argument.
  
      Arguments:
  
      qs: percent-encoded query string to be parsed
  
      keep_blank_values: flag indicating whether blank values in
          percent-encoded queries should be treated as blank strings.  A
          true value indicates that blanks should be retained as blank
          strings.  The default false value indicates that blank values
          are to be ignored and treated as if they were  not included.
  
      strict_parsing: flag indicating what to do with parsing errors. If
          false (the default), errors are silently ignored. If true,
          errors raise a ValueError exception.
  
      encoding and errors: specify how to decode percent-encoded sequences
          into Unicode characters, as accepted by the bytes.decode() method.
  
      Returns a list, as G-d intended.
      """
      qs, _coerce_result = _coerce_args(qs)
      pairs = [s2 for s1 in qs.split('&') for s2 in s1.split(';')]
      r = []
      for name_value in pairs:
          if not name_value and not strict_parsing:
              continue
          nv = name_value.split('=', 1)
          if len(nv) != 2:
              if strict_parsing:
                  raise ValueError("bad query field: %r" % (name_value,))
              # Handle case of a control-name with no equal sign
              if keep_blank_values:
                  nv.append('')
              else:
                  continue
          if len(nv[1]) or keep_blank_values:
              name = nv[0].replace('+', ' ')
              name = unquote(name, encoding=encoding, errors=errors)
              name = _coerce_result(name)
              value = nv[1].replace('+', ' ')
              value = unquote(value, encoding=encoding, errors=errors)
              value = _coerce_result(value)
              r.append((name, value))
      return r
  
  def unquote_plus(string, encoding='utf-8', errors='replace'):
      """Like unquote(), but also replace plus signs by spaces, as required for
      unquoting HTML form values.
  
      unquote_plus('%7e/abc+def') -> '~/abc def'
      """
      string = string.replace('+', ' ')
      return unquote(string, encoding, errors)
  
  _ALWAYS_SAFE = frozenset(bytes(b'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
                                 b'abcdefghijklmnopqrstuvwxyz'
                                 b'0123456789'
                                 b'_.-'))
  _ALWAYS_SAFE_BYTES = bytes(_ALWAYS_SAFE)
  _safe_quoters = {}
  
  class Quoter(collections.defaultdict):
      """A mapping from bytes (in range(0,256)) to strings.
  
      String values are percent-encoded byte values, unless the key < 128, and
      in the "safe" set (either the specified safe set, or default set).
      """
      # Keeps a cache internally, using defaultdict, for efficiency (lookups
      # of cached keys don't call Python code at all).
      def __init__(self, safe):
          """safe: bytes object."""
          self.safe = _ALWAYS_SAFE.union(bytes(safe))
  
      def __repr__(self):
          # Without this, will just display as a defaultdict
          return "<Quoter %r>" % dict(self)
  
      def __missing__(self, b):
          # Handle a cache miss. Store quoted string in cache and return.
          res = chr(b) if b in self.safe else '%{0:02X}'.format(b)
          self[b] = res
          return res
  
  def quote(string, safe='/', encoding=None, errors=None):
      """quote('abc def') -> 'abc%20def'
  
      Each part of a URL, e.g. the path info, the query, etc., has a
      different set of reserved characters that must be quoted.
  
      RFC 2396 Uniform Resource Identifiers (URI): Generic Syntax lists
      the following reserved characters.
  
      reserved    = ";" | "/" | "?" | ":" | "@" | "&" | "=" | "+" |
                    "$" | ","
  
      Each of these characters is reserved in some component of a URL,
      but not necessarily in all of them.
  
      By default, the quote function is intended for quoting the path
      section of a URL.  Thus, it will not encode '/'.  This character
      is reserved, but in typical usage the quote function is being
      called on a path where the existing slash characters are used as
      reserved characters.
  
      string and safe may be either str or bytes objects. encoding must
      not be specified if string is a str.
  
      The optional encoding and errors parameters specify how to deal with
      non-ASCII characters, as accepted by the str.encode method.
      By default, encoding='utf-8' (characters are encoded with UTF-8), and
      errors='strict' (unsupported characters raise a UnicodeEncodeError).
      """
      if isinstance(string, str):
          if not string:
              return string
          if encoding is None:
              encoding = 'utf-8'
          if errors is None:
              errors = 'strict'
          string = string.encode(encoding, errors)
      else:
          if encoding is not None:
              raise TypeError("quote() doesn't support 'encoding' for bytes")
          if errors is not None:
              raise TypeError("quote() doesn't support 'errors' for bytes")
      return quote_from_bytes(string, safe)
  
  def quote_plus(string, safe='', encoding=None, errors=None):
      """Like quote(), but also replace ' ' with '+', as required for quoting
      HTML form values. Plus signs in the original string are escaped unless
      they are included in safe. It also does not have safe default to '/'.
      """
      # Check if ' ' in string, where string may either be a str or bytes.  If
      # there are no spaces, the regular quote will produce the right answer.
      if ((isinstance(string, str) and ' ' not in string) or
          (isinstance(string, bytes) and b' ' not in string)):
          return quote(string, safe, encoding, errors)
      if isinstance(safe, str):
          space = str(' ')
      else:
          space = bytes(b' ')
      string = quote(string, safe + space, encoding, errors)
      return string.replace(' ', '+')
  
  def quote_from_bytes(bs, safe='/'):
      """Like quote(), but accepts a bytes object rather than a str, and does
      not perform string-to-bytes encoding.  It always returns an ASCII string.
      quote_from_bytes(b'abc def\x3f') -> 'abc%20def%3f'
      """
      if not isinstance(bs, (bytes, bytearray)):
          raise TypeError("quote_from_bytes() expected bytes")
      if not bs:
          return str('')
      ### For Python-Future:
      bs = bytes(bs)
      ###
      if isinstance(safe, str):
          # Normalize 'safe' by converting to bytes and removing non-ASCII chars
          safe = str(safe).encode('ascii', 'ignore')
      else:
          ### For Python-Future:
          safe = bytes(safe)
          ###
          safe = bytes([c for c in safe if c < 128])
      if not bs.rstrip(_ALWAYS_SAFE_BYTES + safe):
          return bs.decode()
      try:
          quoter = _safe_quoters[safe]
      except KeyError:
          _safe_quoters[safe] = quoter = Quoter(safe).__getitem__
      return str('').join([quoter(char) for char in bs])
  
  def urlencode(query, doseq=False, safe='', encoding=None, errors=None):
      """Encode a sequence of two-element tuples or dictionary into a URL query string.
  
      If any values in the query arg are sequences and doseq is true, each
      sequence element is converted to a separate parameter.
  
      If the query arg is a sequence of two-element tuples, the order of the
      parameters in the output will match the order of parameters in the
      input.
  
      The query arg may be either a string or a bytes type. When query arg is a
      string, the safe, encoding and error parameters are sent the quote_plus for
      encoding.
      """
  
      if hasattr(query, "items"):
          query = query.items()
      else:
          # It's a bother at times that strings and string-like objects are
          # sequences.
          try:
              # non-sequence items should not work with len()
              # non-empty strings will fail this
              if len(query) and not isinstance(query[0], tuple):
                  raise TypeError
              # Zero-length sequences of all types will get here and succeed,
              # but that's a minor nit.  Since the original implementation
              # allowed empty dicts that type of behavior probably should be
              # preserved for consistency
          except TypeError:
              ty, va, tb = sys.exc_info()
              raise_with_traceback(TypeError("not a valid non-string sequence "
                                             "or mapping object"), tb)
  
      l = []
      if not doseq:
          for k, v in query:
              if isinstance(k, bytes):
                  k = quote_plus(k, safe)
              else:
                  k = quote_plus(str(k), safe, encoding, errors)
  
              if isinstance(v, bytes):
                  v = quote_plus(v, safe)
              else:
                  v = quote_plus(str(v), safe, encoding, errors)
              l.append(k + '=' + v)
      else:
          for k, v in query:
              if isinstance(k, bytes):
                  k = quote_plus(k, safe)
              else:
                  k = quote_plus(str(k), safe, encoding, errors)
  
              if isinstance(v, bytes):
                  v = quote_plus(v, safe)
                  l.append(k + '=' + v)
              elif isinstance(v, str):
                  v = quote_plus(v, safe, encoding, errors)
                  l.append(k + '=' + v)
              else:
                  try:
                      # Is this a sufficient test for sequence-ness?
                      x = len(v)
                  except TypeError:
                      # not a sequence
                      v = quote_plus(str(v), safe, encoding, errors)
                      l.append(k + '=' + v)
                  else:
                      # loop over the sequence
                      for elt in v:
                          if isinstance(elt, bytes):
                              elt = quote_plus(elt, safe)
                          else:
                              elt = quote_plus(str(elt), safe, encoding, errors)
                          l.append(k + '=' + elt)
      return str('&').join(l)
  
  # Utilities to parse URLs (most of these return None for missing parts):
  # unwrap('<URL:type://host/path>') --> 'type://host/path'
  # splittype('type:opaquestring') --> 'type', 'opaquestring'
  # splithost('//host[:port]/path') --> 'host[:port]', '/path'
  # splituser('user[:passwd]@host[:port]') --> 'user[:passwd]', 'host[:port]'
  # splitpasswd('user:passwd') -> 'user', 'passwd'
  # splitport('host:port') --> 'host', 'port'
  # splitquery('/path?query') --> '/path', 'query'
  # splittag('/path#tag') --> '/path', 'tag'
  # splitattr('/path;attr1=value1;attr2=value2;...') ->
  #   '/path', ['attr1=value1', 'attr2=value2', ...]
  # splitvalue('attr=value') --> 'attr', 'value'
  # urllib.parse.unquote('abc%20def') -> 'abc def'
  # quote('abc def') -> 'abc%20def')
  
  def to_bytes(url):
      """to_bytes(u"URL") --> 'URL'."""
      # Most URL schemes require ASCII. If that changes, the conversion
      # can be relaxed.
      # XXX get rid of to_bytes()
      if isinstance(url, str):
          try:
              url = url.encode("ASCII").decode()
          except UnicodeError:
              raise UnicodeError("URL " + repr(url) +
                                 " contains non-ASCII characters")
      return url
  
  def unwrap(url):
      """unwrap('<URL:type://host/path>') --> 'type://host/path'."""
      url = str(url).strip()
      if url[:1] == '<' and url[-1:] == '>':
          url = url[1:-1].strip()
      if url[:4] == 'URL:': url = url[4:].strip()
      return url
  
  _typeprog = None
  def splittype(url):
      """splittype('type:opaquestring') --> 'type', 'opaquestring'."""
      global _typeprog
      if _typeprog is None:
          import re
          _typeprog = re.compile('^([^/:]+):')
  
      match = _typeprog.match(url)
      if match:
          scheme = match.group(1)
          return scheme.lower(), url[len(scheme) + 1:]
      return None, url
  
  _hostprog = None
  def splithost(url):
      """splithost('//host[:port]/path') --> 'host[:port]', '/path'."""
      global _hostprog
      if _hostprog is None:
          import re
          _hostprog = re.compile('^//([^/?]*)(.*)$')
  
      match = _hostprog.match(url)
      if match:
          host_port = match.group(1)
          path = match.group(2)
          if path and not path.startswith('/'):
              path = '/' + path
          return host_port, path
      return None, url
  
  _userprog = None
  def splituser(host):
      """splituser('user[:passwd]@host[:port]') --> 'user[:passwd]', 'host[:port]'."""
      global _userprog
      if _userprog is None:
          import re
          _userprog = re.compile('^(.*)@(.*)$')
  
      match = _userprog.match(host)
      if match: return match.group(1, 2)
      return None, host
  
  _passwdprog = None
  def splitpasswd(user):
      """splitpasswd('user:passwd') -> 'user', 'passwd'."""
      global _passwdprog
      if _passwdprog is None:
          import re
          _passwdprog = re.compile('^([^:]*):(.*)$',re.S)
  
      match = _passwdprog.match(user)
      if match: return match.group(1, 2)
      return user, None
  
  # splittag('/path#tag') --> '/path', 'tag'
  _portprog = None
  def splitport(host):
      """splitport('host:port') --> 'host', 'port'."""
      global _portprog
      if _portprog is None:
          import re
          _portprog = re.compile('^(.*):([0-9]+)$')
  
      match = _portprog.match(host)
      if match: return match.group(1, 2)
      return host, None
  
  _nportprog = None
  def splitnport(host, defport=-1):
      """Split host and port, returning numeric port.
      Return given default port if no ':' found; defaults to -1.
      Return numerical port if a valid number are found after ':'.
      Return None if ':' but not a valid number."""
      global _nportprog
      if _nportprog is None:
          import re
          _nportprog = re.compile('^(.*):(.*)$')
  
      match = _nportprog.match(host)
      if match:
          host, port = match.group(1, 2)
          try:
              if not port: raise ValueError("no digits")
              nport = int(port)
          except ValueError:
              nport = None
          return host, nport
      return host, defport
  
  _queryprog = None
  def splitquery(url):
      """splitquery('/path?query') --> '/path', 'query'."""
      global _queryprog
      if _queryprog is None:
          import re
          _queryprog = re.compile('^(.*)\?([^?]*)$')
  
      match = _queryprog.match(url)
      if match: return match.group(1, 2)
      return url, None
  
  _tagprog = None
  def splittag(url):
      """splittag('/path#tag') --> '/path', 'tag'."""
      global _tagprog
      if _tagprog is None:
          import re
          _tagprog = re.compile('^(.*)#([^#]*)$')
  
      match = _tagprog.match(url)
      if match: return match.group(1, 2)
      return url, None
  
  def splitattr(url):
      """splitattr('/path;attr1=value1;attr2=value2;...') ->
          '/path', ['attr1=value1', 'attr2=value2', ...]."""
      words = url.split(';')
      return words[0], words[1:]
  
  _valueprog = None
  def splitvalue(attr):
      """splitvalue('attr=value') --> 'attr', 'value'."""
      global _valueprog
      if _valueprog is None:
          import re
          _valueprog = re.compile('^([^=]*)=(.*)$')
  
      match = _valueprog.match(attr)
      if match: return match.group(1, 2)
      return attr, None
  