@gen.coroutine
  def _Update(self):
    """Updates the database:
       1. Revives any followers that have removed the viewpoint.
       2. Updates the viewpoint metadata.
    """
    # Revive any REMOVED followers.
    yield gen.Task(Follower.ReviveRemovedFollowers, self._client, self._followers)

    # Update the viewpoint metadata.
    assert self._vp_dict not in 'update_seq', self._vp_dict
    self._viewpoint.UpdateFromKeywords(**self._vp_dict)
    yield gen.Task(self._viewpoint.Update, self._client)
dataset/ETHPy150Open viewfinderco/viewfinder/backend/op/update_viewpoint_op.py/UpdateViewpointOperation._Update/swapped operands of `not in`