PEP8: Never use equality operators to compare to singletons

[cclauss]

https://peps.python.org/pep-0008/#programming-recommendations

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

% ruff rule E712

true-false-comparison (E712)

Derived from the pycodestyle linter.

Fix is always available.

What it does

Checks for equality comparisons to boolean literals.

Why is this bad?

PEP 8 recommends against using the equality operators == and != to
compare values to True or False.

Instead, use if cond: or if not cond: to check for truth values.

If you intend to check if a value is the boolean literal True or False,
consider using is or is not to check for identity instead.

Example

if foo == True:
    ...

if bar == False:
    ...

Use instead:

if foo:
    ...

if not bar:
    ...

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.