Load this tree from a dumb data object for serialisation.

        The object must have attributes tree_size:int and hashes:list.

def load(self, other: merkle_tree.MerkleTree):
        """Load this tree from a dumb data object for serialisation.

        The object must have attributes tree_size:int and hashes:list.
        """
        self._update(other.tree_size, other.hashes)