In order to be callable, a python class should implement the __call__ method.
This rule raises an issue when a non-callable object is called.
class MyClass:
pass
myvar = MyClass()
myvar() # Noncompliant
none_var = None
none_var() # Noncompliant
class MyClass:
def __call__(self):
print("called")
myvar = MyClass()
myvar()