Still what you are doing is a bit strange.
class Dummy():
    def __init__(self):
        self.x = {'dummy':None}
    def __call__(self, *args, **kwargs):
        return self.x['dummy']
        
b=Dummy()
b()=a
  File "<ipython-input-8-e815e88d0509>", line 1
    b()=a
         ^
SyntaxError: can't assign to function call

I would say it’s not possible to return something from an object call and assign it to a variable
as you are doing there. My IDE agrees.
A(input) = a