def read(self, ids: torch.Tensor = None):
        """Read the feature by index.

        Parameters
        ----------
        ids : torch.Tensor, optional
            The index of the feature. If specified, only the specified indices
            of the feature are read. If None, the entire feature is returned.

        Returns
        -------
        torch.Tensor
            The read feature.
        """
        if ids is None:
            return self._fallback_feature.read()
        return self._feature.query_and_replace(
            ids.cpu(), self._fallback_feature.read, self._offset
        ).to(ids.device)
Read the feature by index.

        Parameters
        ----------
        ids : torch.Tensor, optional
            The index of the feature. If specified, only the specified indices
            of the feature are read. If None, the entire feature is returned.

        Returns
        -------
        torch.Tensor
            The read feature.
        
python/dgl/graphbolt/impl/cpu_cached_feature.py