== Why is this an issue? A class without an explicit extension of object (``++class ClassName(object)++``) is considered an old-style class, and ``++__slots__++`` declarations are ignored in old-style classes. Having such a declaration in an old-style class could be confusing for maintainers and lead them to make false assumptions about the class. === Noncompliant code example [source,python] ---- class A: __slots__ = ["id"] # Noncompliant; this is ignored def __init__(self): self.id = id self.name = "name" # name wasn't declared in __slots__ but there's no error a = A() ---- === Compliant solution [source,python] ---- class A(object): # Converting to a new-style class is the preferred method of addressing this issue __slots__ = ["id"] def __init__(self): self.id = id self.name = "name" # "name" is not listed in __slots__, so as expected there is an error in this line a = A() ---- or [source,python] ---- class A: def __init__(self): self.id = id self.name = "name" a = A() ---- ifdef::env-github,rspecator-view[] ''' == Implementation Specification (visible only on this page) === Message Either add "(object)" to this class declaration or remove the "__slots__" declaration. endif::env-github,rspecator-view[]