def blocks(self) -> list:
        """DGL blocks extracted from `MiniBatch` containing graphical structures
        and ID mappings.
        """
        if not self.sampled_subgraphs:
            return None

        if self._blocks is None:
            self._blocks = self.compute_blocks()
        return self._blocks
DGL blocks extracted from `MiniBatch` containing graphical structures
        and ID mappings.
        
python/dgl/graphbolt/minibatch.py