Python `if x is not None` or `if not x is None`?

The proper way to check if a variable x is not None in Python is to use if x is not None.

if x is not None:
    # do something

It is not recommended to use if not x is None as it is less readable, and the double negation can be confusing.

if not x is None:  # not recommended
    # do something

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It is also common and more pythonic to use if x instead of if x is not None

if x:
    # do something

As None is considered as a False value in python, The above statement will also check if x is not None