code: def is_visible(self, pos: Union[Point2, Point3, Unit]) -> bool:
          
          # more info: https://github.com/Blizzard/s2client-proto/blob/9906df71d6909511907d8419b33acc1a3bd51ec0/s2clientprotocol/spatial.proto#L19
          assert isinstance(pos, (Point2, Point3, Unit))
          pos = pos.position.to2.rounded
          return self.state.visibility[pos] == 2
docs: Returns True if you have vision on a grid point.