Python Classes: differences between inheritance and create a parent class instance inside the child (class composition)

Question

I have the following problem:

I have a class A , that only stores a big numbers of variables; then I have 3 classes, B , C , D , that inherit A to define more complex objects (different in each of the 3 classes) that depend on the set of variables defined in A . Finally there is a class E that has to inherit only one between B , C , D .

Since I want the flexibility to choose each time the class to include in E I don't want a fixed Parent name as argument of E . To do so, instead of inherit the class I'm creating a class instance in the __init__() method (to access all the parent's methods and attributes as well); I report below the 2 different way to better express the idea. My question is:

Is there some cons in proceeding my way, or, more in general, which are the differences between the 2 approaches?

class E(D):
    def __init__(self, argsE, argsPar):
        super().__init__(self, argsPar)
    ...

(in the example above I have to specify the parent class, which I want to give in input and not to be fixed)

class E:
    def __init__(self, parent, argsE, argsPar):
        if(parent=='B')
            self.parent = B(argsPar)
        if(parent=='C')
            self.parent = C(argsPar) 
        if(parent=='D')
            self.parent = D(argsPar)
      
    ...

Answer 1

Since I want the flexibility to choose each time the class to include in E I don't want a fixed Parent name as argument of E .

Then just exploit type to dynamically create class, consider following example

class A:
    pass
class B:
    pass
choice = input("Shall C inherit A xor B?")
if choice == "A":
    C = type("C", (A,), {})
elif choice == "B":
    C = type("C", (B,), {})
else:
    exit()
print(issubclass(C,A))  # True if choice was A else False
print(issubclass(C,B))  # True if choice was B else False

Third argument to type should be

dictionary contains attribute and method definitions for the class body

In above example for brevity sake empty dict was used,