code: def _is_url(url):
      """Check to see if a URL has a valid protocol.
  
      Parameters
      ----------
      url : str or unicode
  
      Returns
      -------
      isurl : bool
          If `url` has a valid protocol return True otherwise False.
      """
      try:
          return parse_url(url).scheme in _VALID_URLS
      except Exception:
          return False
  
imports: import codecs
  from contextlib import closing, contextmanager
  import csv
  import mmap
  import os
  import zipfile
  import pandas.compat
  from pandas.compat import BytesIO, StringIO, string_types, text_type
  from pandas.errors import AbstractMethodError, DtypeWarning, EmptyDataError, ParserError, ParserWarning
  from pandas.core.dtypes.common import is_file_like, is_number
  from pandas.io.formats.printing import pprint_thing
label_desc: Use image node_id 1 for calling a global function with example usage: _is_url(url) and returns: unknown, False