class_docstr: :param headers:
      An iterable of field-value pairs. Must not contain multiple field names
      when compared case-insensitively.
  
  :param kwargs:
      Additional field-value pairs to pass in to ``dict.update``.
  
  A ``dict`` like container for storing HTTP Headers.
  
  Field names are stored and compared case-insensitively in compliance with
  RFC 7230. Iteration provides the first case-sensitive key seen for each
  case-insensitive pair.
  
  Using ``__setitem__`` syntax overwrites fields that compare equal
  case-insensitively in order to maintain ``dict``'s api. For fields that
  compare equal, instead create a new ``HTTPHeaderDict`` and use ``.add``
  in a loop.
  
  If multiple fields that are equal case-insensitively are passed to the
  constructor or ``.update``, the behavior is undefined and some will be
  lost.
  
  >>> headers = HTTPHeaderDict()
  >>> headers.add('Set-Cookie', 'foo=bar')
  >>> headers.add('set-cookie', 'baz=quxx')
  >>> headers['content-length'] = '7'
  >>> headers['SET-cookie']
  'foo=bar, baz=quxx'
  >>> headers['Content-Length']
  '7'
docstr: Read headers from a Python 2 httplib message object.
docstr_tok: ["Read","headers","from","a","Python","2","httplib","message","object","."]
code: def from_httplib(cls, message):  # Python 2
      """Read headers from a Python 2 httplib message object."""
      # python2.7 does not expose a proper API for exporting multiheaders
      # efficiently. This function re-reads raw lines from the message
      # object and extracts the multiheaders properly.
      headers = []
  
      for line in message.headers:
          if line.startswith((" ", "\t")):
              key, value = headers[-1]
              headers[-1] = (key, value + "\r\n" + line.rstrip())
              continue
  
          key, value = line.split(":", 1)
          headers.append((key, value.strip()))
  
      return cls(headers)
  
imports: import sys
  import requests
label_desc: Use image node_id 21 for calling the HTTPHeaderDict obj's underlying member method code with example usage: obj.from_httplib(cls, message) and returns: cls