def union(self, operand1_name, operand2_name, output_name):
        """Compute the union of two mask arrays in the KVStore."""
        # Each trainer computes its own result from its local storage.
        self._data_store[output_name][:] = (
            self._data_store[operand1_name] | self._data_store[operand2_name]
        )
Compute the union of two mask arrays in the KVStore.
python/dgl/distributed/kvstore.py