code: def add(self, data_object_replica: DataObjectReplica):
          
          if data_object_replica.number in self._data:
              raise ValueError(
                      "Data object replica with number %d already exists in this collection" % data_object_replica.number)
          self._data[data_object_replica.number] = data_object_replica
docs: Adds the given data object replica to this collection. Will raise a `ValueError` if a data object replica with
          the same number already exists.
          :param data_object_replica: the data object replica to add