code: def __query(self, query, tagid=None):
          
          if self.encrypted:
              document = self.decrypted_document
          else:
              document = self.document
          return OneLogin_Saml2_Utils.query(document, query, None, tagid)
docs: Extracts nodes that match the query from the Response
  
          :param query: Xpath Expresion
          :type query: String
  
          :param tagid: Tag ID
          :type query: String
  
          :returns: The queried nodes
          :rtype: list