code: def get_by_number(self, number: int) -> Optional[DataObjectReplica]:
          
          return self._data.get(number, None)
docs: Gets the data object replica in this collection with the given number. Will return `None` if such replica does
          not exist.
          :param number: the number of the data object replica to get
          :return: the data object replica in this collection with the given number