Dynamically created classes with the same name

Question

I'm trying to dynamically create subclasses in Python with type:

class A:
    @classmethod
    def create_subclass(cls, name, attrs):
        return type(name, (cls,), attrs)

for i in range(5):
    x = A.create_subclass("B", {"func": abs})

print(A.__subclasses__())

and here's what I see in the output:

[<class '__main__.B'>, <class '__main__.B'>, <class '__main__.B'>, <class '__main__.B'>, <class '__main__.B'>]

Obviously, this was not my intention. Two questions in that respect:

1. How does Python handles multiple classes with identical names?
2. What is a pythonic way to handle it? Of course, I can look up the name in the already existing subclasses, but then how to deal with namespaces/modules?

Answer 1

Python doesn't care overmuch about the classname, these will be different classes, you just need to have a mechanism to save and look up the classes you want.

class A:

    def __repr__(self):
        return f"{self.__class__.__name__} floor={self.floor}"


    @classmethod
    def create_subclass(cls, name, attrs):
        return type(name, (cls,), attrs)

di_cls = {}
#save them in a dictionary
for i in range(5):
    di_cls[i] = A.create_subclass("B", {"func": abs, "floor" : i})

for i, cls in di_cls.items():
    print(f"{cls()}")

class config:
    #put them in hierarchical namespaces
    cls_level1 = A.create_subclass("B", {"func": abs, "floor" : 11})

    class level2:
        cls_level2 = A.create_subclass("B", {"func": abs, "floor" : 22})

print(f"{config.cls_level1()=}")
print(f"{config.level2.cls_level2()}")

l1 = config.cls_level1()
l2 = config.level2.cls_level2()

print(f"{isinstance(l1, A)=}")
print(f"{isinstance(l2, A)=}")
print(f"{isinstance(l2, config.level2.cls_level2)=}")
print(f"{isinstance(l2, config.cls_level1)=}")

output:

B floor=0
B floor=1
B floor=2
B floor=3
B floor=4
config.cls_level1()=B floor=11
B floor=22
isinstance(l1, A)=True
isinstance(l2, A)=True
isinstance(l2, config.level2.cls_level2)=True
isinstance(l2, config.cls_level1)=False