Skip to content

none-comparison (E711)#

Derived from the pycodestyle linter.

Fix is always available.

What it does#

Checks for comparisons to None which are not using the is operator.

Why is this bad?#

According to PEP 8, "Comparisons to singletons like None should always be done with is or is not, never the equality operators."


if arg != None:
if None == arg:

Use instead:

if arg is not None:

Fix safety#

This rule's fix is marked as unsafe, as it may alter runtime behavior when used with libraries that override the ==/__eq__ or !=/__ne__ operators. In these cases, is/is not may not be equivalent to ==/!=. For more information, see this issue.