code: def update(self, payload):
          
          try:
              result = self.get_one()
              if 'sys_id' not in result:
                  raise NoResults()
          except MultipleResults:
              raise MultipleResults("Update of multiple records is not supported")
          except NoResults as e:
              e.args = ('Cannot update a non-existing record',)
              raise
  
          if not isinstance(payload, dict):
              raise InvalidUsage("Update payload must be of type dict")
  
          response = self.session.put(self._get_table_url(sys_id=result['sys_id']), data=json.dumps(payload))
          return self._get_content(response)
docs: Updates the queried record with `payload` and returns the updated record after validating the response
  
          :param payload: Payload to update the record with
          :raise:
              :NoResults: if query returned no results
              :MultipleResults: if query returned more than one result (currently not supported)
          :return:
              - The updated record