invalid-bytes-return-type (PLE0308)

Derived from the Pylint linter.

What it does

Checks for __bytes__ implementations that return types other than bytes.

Why is this bad?

The __bytes__ method should return a bytes object. Returning a different type may cause unexpected behavior.

Example

class Foo:
    def __bytes__(self):
        return 2

Use instead:

class Foo:
    def __bytes__(self):
        return b"2"

References

• Python documentation: The __bytes__ method