`QObject.sender()` None if slot is inherited

from PySide6 import QtCore 

class A(QtCore.QObject):
     @QtCore.Signal
     def mySignal(self):
         ... 

     def __init__(self) -> None:
         super().__init__()
         self.mySignal.connect(self.mySlot) 

     @QtCore.Slot()
     def mySlot(self):
         print(self.sender()) 

 class B(A):
     ... 

 if __name__ == "__main__":
     a = A()
     b = B()
     a.mySignal.emit()
     b.mySignal.emit()

<__main__.A(0x18498f7dd20) at 0x0000018499327380>
None