def is_empty_tuple(node: LN) -> bool:
    """Return True if `node` holds an empty tuple."""
    return (
        node.type == syms.atom
        and len(node.children) == 2
        and node.children[0].type == token.LPAR
        and node.children[1].type == token.RPAR
    )
Return True if `node` holds an empty tuple.
src/black/nodes.py