[Solved] Please, help me find a simple mistake

[AlekseyPython]

Fedora 34, Python 3.9.5

from PyQt5 import QtWidgets
from PyQt5.QtWidgets import QWidget

class M_A(type(QWidget), type):pass
class A(QWidget, metaclass=M_A):
    def __init__(self):
        QWidget.__init__(self)
        
class B:
    def __init__(self, controller):
        self.controller = controller
        
        
class M_C(type(A), type(B)):pass
class C(A, B, metaclass=M_C):
    def __init__(self, controller):
        A.__init__(self)
        B.__init__(self, controller)
        
        
app = QtWidgets.QApplication([])
C(controller=19)

Error:
Traceback (most recent call last):
  File "/home/ivan/eclipse-workspace/GompertzLaw/Exp.py", line 22, in <module>
    C(controller=19)
  File "/home/ivan/eclipse-workspace/GompertzLaw/Exp.py", line 17, in __init__
    A.__init__(self)
  File "/home/ivan/eclipse-workspace/GompertzLaw/Exp.py", line 7, in __init__
    QWidget.__init__(self)
TypeError: __init__() missing 1 required positional argument: 'controller'

Where is the mistake?

[topfox]

Is your error that controller is defined as a positional argument, but you are calling it as a keyword argument?

[AlekseyPython]

Decision:

class B:
    def __init__(self, controller=0):
        self.controller = controller