def unpin_memory_(self):
        """Unpin the storage pinned by ``pin_memory_`` method.

        Does nothing if the storage is not pinned by ``pin_memory_`` method, even if
        it is actually in page-locked memory.
        """
        if self.pinned_by_dgl:
            self._data_nd.unpin_memory_()
            self._data_nd = None
            self.pinned_by_dgl = False
Unpin the storage pinned by ``pin_memory_`` method.

        Does nothing if the storage is not pinned by ``pin_memory_`` method, even if
        it is actually in page-locked memory.
        
python/dgl/frame.py