def __init__(
self,
val: Union[int, float, str, Callable],
left: Optional[ExpressionTreeNode] = None,
right: Optional[ExpressionTreeNode] = None,
) -> None:
Node.__init__(self, val, left, right)
def __init__(self, val: int) -> None:
Node.__init__(self, val)
self.locked = False
self.parent = None