parameters: (url_str)
docstring: Returns scheme component of a URL string.
docstring_summary: Returns scheme component of a URL string.
docstring_tokens: Returns scheme component of a URL string .
function: def _GetSchemeFromUrlString(url_str):
    """Returns scheme component of a URL string."""
  
    end_scheme_idx = url_str.find('://')
    if end_scheme_idx == -1:
      # File is the default scheme.
      return 'file'
    else:
      return url_str[0:end_scheme_idx].lower()
function_tokens: def _GetSchemeFromUrlString ( url_str ) : end_scheme_idx = url_str . find ( '://' ) if end_scheme_idx == - 1 : # File is the default scheme. return 'file' else : return url_str [ 0 : end_scheme_idx ] . lower ( )