Can I dinamically determine module and class to be used? [duplicate]

This question already has an answer here:

• How to dynamically load a Python class 6 answers

I am not sure how to word this.

Basically, what am I looking for is a way to call a method from a variable class.

Something like this:

var = "MyWonderfulClass"
module = "my_wonderful_class"
if $module.$class.likes_spam():
    print("I like trains")

How to do this?

EDIT: I do not want to load modules dinamically, I want to call methods of a module/class determined at run time.