def is_function(self):
        """return True if callback is a vanilla plain jane function"""
        if self.is_instance() or self.is_class(): return False
        return isinstance(self.callback, (Callable, classmethod))
def is_function(self):
        """return True if callback is a vanilla plain jane function"""
        if self.is_instance() or self.is_class(): return False
        return isinstance(self.callback, (Callable, classmethod))
def is_function ( self ) : if self . is_instance ( ) or self . is_class ( ) : return False return isinstance ( self . callback , ( Callable , classmethod ) )
return True if callback is a vanilla plain jane function
return True if callback is a vanilla plain jane function