Is cicular inheritance allowed in python?

Question

class A:
def method(self):
print("A method")

class B(A):
def another_method(self):
print("B method")

class C(B):
def third_method(self):
print("C method")
class A(C):
def fourth_method(self):
print("D method")
c = C()
c.method()
c.another_method()
c.third_method()
A().fourth_method ()

Answer 1

Apparently it is, since if you replace the last 5 lines with the following:

a = A()

a.method()
a.another_method()
a.third_method()
a.fourth_method()

The code runs fine, so class A seems to have inherited the other three methods.

Edit:
I really should've googled this before posing my answer, but If 李立威's idea of circular inheritance is what it is, then I don't think it exists in Python.

Answer 2

To my understanding, no. In your code, you've redefined an A(C) class, that is, you've impliciy overwrite (or del) the original class A. However, since class B is inherited from the original class A, it's method "method" remains. (just like this logic:
a=1
b=a+1
c=b+1
a=c+1 #this "a" variable is a new one, which is different from the original variable "a". The original variable "a" or the original class A has been overwritten. )

If the circular inheritance truely exists, then the following code should be valid:

b=B()
b.fourth_method()

And that is not working.

Edit:
see page 3 at
https://www.sololearn.com/learn/JUMP_LINK__&&__Python__&&__JUMP_LINK/2469/