Best way to check if an object is None?

问题

How should I fix this error? Seems like an unresolved issue in this repository: https://github.com/shayanzare007/EntitySentiment/issues/7

$ python RunRNN.py 
Number of unique words: 9869
Opening the file...
File successfully read
Opening the file...
File successfully read
Opening the file...
File successfully read
Number of training samples 5003
Traceback (most recent call last):
  File "RunRNN.py", line 84, in <module>
    curve = model.train_sgd(X,Y,idxiter_random,None,400,400) 
  File "/scratch2/debate_tweets/sentiment/EntitySentiment/nn/base.py", line 386, in train_sgd
    if idxiter == None: # default training schedule
ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

回答1:

When testing an object for nullity, the recommended practice is to always use is:

if idxiter is None:
    ...

It's safer, especially because not all objects support equality comparisons with None.

来源：https://stackoverflow.com/questions/49186324/best-way-to-check-if-an-object-is-none