implicit-return-value (RET502)

Derived from the flake8-return linter.

Fix is always available.

What it does

Checks for the presence of a return statement with no explicit value, for functions that return non-None values elsewhere.

Why is this bad?

Including a return statement with no explicit value can cause confusion when other return statements in the function return non-None values. Python implicitly assumes return None if no other return value is present. Adding an explicit return None can make the code more readable by clarifying intent.

Example

def foo(bar):
    if not bar:
        return
    return 1

Use instead:

def foo(bar):
    if not bar:
        return None
    return 1