TypeError: '>' not supported between instances of 'builtin_function_or_method' and 'int'

问题：

File "D:/code/pythonl2/main.py", line 15, in forward
    while X.abs().sum > 1:
TypeError: '>' not supported between instances of 'builtin_function_or_method' and 'int'

　　分析：是sum()不是sum