code: def get_update(self, id, update_number, project=None):
          
          route_values = {}
          if project is not None:
              route_values['project'] = self._serialize.url('project', project, 'str')
          if id is not None:
              route_values['id'] = self._serialize.url('id', id, 'int')
          if update_number is not None:
              route_values['updateNumber'] = self._serialize.url('update_number', update_number, 'int')
          response = self._send(http_method='GET',
                                location_id='6570bf97-d02c-4a91-8d93-3abe9895b1a9',
                                version='5.1-preview.3',
                                route_values=route_values)
          return self._deserialize('WorkItemUpdate', response)
docs: GetUpdate.
          [Preview API] Returns a single update for a work item
          :param int id:
          :param int update_number:
          :param str project: Project ID or project name
          :rtype: :class:`<WorkItemUpdate> <azure.devops.v5_1.work-item-tracking.models.WorkItemUpdate>`