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
----
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
----
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
