code: def _EncodeParameters(self, parameters):
          
  
          if parameters is None:
              return None
          else:
              return urlencode(dict([(k, self._Encode(v)) for k, v in list(parameters.items()) if v is not None]))
docs: Return a string in key=value&key=value form.
          :param parameters: A dict of (key, value) tuples, where value is encoded as specified by self._encoding
          :return:A URL-encoded string in "key=value&key=value" form