Dynamic inheritance in Python

Question

Say I have 2 different implementations of a class

class ParentA:     def initialize(self):         pass      def some_event(self):         pass      def order(self, value):         # handle order in some way for Parent A   class ParentB:     def initialize(self):         pass      def some_event(self):         pass      def order(self, value):         # handle order in another for Parent B 

How can I dynamically let some 3rd class inherit from either ParentA or ParentB based on something like this?

class MyCode:     def initialize(self):         self.initial_value = 1      def some_event(self):         # handle event         order(self.initial_value)   # let MyCode inherit from ParentA and run run(my_code, ParentA) 

Answer 1

Simply store the class-object in a variable (in the example below, it is named base), and use the variable in the base-class-spec of your class statement.

def get_my_code(base):      class MyCode(base):         def initialize(self):           ...      return MyCode  my_code = get_my_code(ParentA) 

Answer 2

Also, you can use type builtin. As callable, it takes arguments: name, bases, dct (in its simplest form).

def initialize(self):     self.initial_value = 1  def some_event(self):     # handle event     order(self.initial_value)  subclass_body_dict = {     "initialize": initialize,     "some_event": some_event }  base_class = ParentA # or ParentB, as you wish  MyCode = type("MyCode", (base_class, ), subclass_body_dict) 

This is more explicit than snx2 solution, but still - I like his way better.

PS. of course, you dont have to store base_class, nor subclass_body_dict, you can build those values in type() call like:

MyCode = type("MyCode", (ParentA, ), {         "initialize": initialize,         "some_event": some_event     })