Memoize Django model's method.

memoize.py

import functools


def memoize_django_model_method(obj):

    @functools.wraps(obj)
    def memoizer(*args, **kwargs):
        # Get the model instance
        instance = args[0]

        if not hasattr(instance, "__memoize_cache"):
            # If not present yet, add a dictionnary to store values for this instance.
            # This dictionnary keys will be filled by the method name + args.
            instance.__memoize_cache = {}

        # Creating the key base on method_name + args passed to the function
        key = str(obj.__name__) + str(kwargs)

        if not key in instance.__memoize_cache:
            # This is the first time we call this function on this instance with thoses args.
            instance.__memoize_cache[key] = obj(*args, **kwargs)

        # Return the value stored.
        return instance.__memoize_cache[key]
    return memoizer