@wraps(func)
def func_wrapper(*args, **kwargs):
    if args[0]._destroyed:
        raise ExistError('Cannot perform operation on deleted node')
    return func(*args, **kwargs)
@wraps(func)
def func_wrapper(*args, **kwargs):
    if args[0]._destroyed:
        raise ExistError('Cannot perform operation on deleted node')
    return func(*args, **kwargs)