code: def request(input, representation, resolvers=None, get3d=False, tautomers=False, **kwargs):
      
      url = construct_api_url(input, representation, resolvers, get3d, tautomers, **kwargs)
      log.debug('Making request: %s', url)
      response = urlopen(url)
      return etree.parse(response).getroot()
docs: Make a request to CIR and return the XML response.
  
      :param string input: Chemical identifier to resolve
      :param string representation: Desired output representation
      :param list(string) resolvers: (Optional) Ordered list of resolvers to use
      :param bool get3d: (Optional) Whether to return 3D coordinates (where applicable)
      :param bool tautomers: (Optional) Whether to return all tautomers
      :returns: XML response from CIR
      :rtype: Element
      :raises HTTPError: if CIR returns an error code
      :raises ParseError: if CIR response is uninterpretable