Question

I want to code the apply_method function:

class A:
   def calc(self, num):
       return num 

def apply_method(class_method, *args, **kwargs):
    # Identify class module A from class_method: Is this possible?
    # Import class module A
    # Create an instance of the class A, say obj
    # return obj.class_method(*args, **kwargs)
    pass

class_method = A.calc
input_num = 5
return apply_method(class_method, 5) 

It is guaranteed that the module for class A is available to be imported wherever apply_method gets called.

Is all the information necessary to create apply_method available inside class_method?

The reason I need this: apply_method is a callback. The callback only contains a function and parameters. The callback needs to be made across hundreds of different classes. In the absence of this generic method, I will need to handle callbacks very specifically for each of the classes.

Answer 1

Play around with some of the __ methods in the interpreter. Everything you need should be available in one form or another:

In [6]: class_method = A.calc
In [7]: class_method.__class__
Out[7]: <type 'instancemethod'>

In [8]: class_method.__func__
Out[8]: <function calc at 0x101625938>

In [9]: class_method.im_class
Out[9]: <class __main__.A at 0x10161ea10>

In [10]: class_method.im_class == A
Out[10]: True

In [11]: class_method.im_class.__module__
Out[11]: '__main__'