PY3.E1129
Not context manager
Used when an instance in a with statement doesn't implement the context manager protocol( enter / exit ).
Noncompliant Code:
Copy
                                                    
                                                
                                                class Ctx:
    def __enter__(self):
        pass
with Ctx() as ctx:
    pass
                                                    Compliant Code:
Copy
                                                    
                                                
                                            class Ctx:
    def __enter__(self):
        pass
    def __exit__(self, *exc):
        pass
with Ctx() as ctx:
    pass