from django.core.cache import cache
def stales_cache(cache_key):
    def paramed_decorator(func):
        def decorated(self, *args, **kw):
            key = cache_key % self.__dict__
            cache.delete(key)
            return func(self, *args, **kw)
        decorated.__doc__ = func.__doc__
        decorated.__dict__ = func.__dict__
        return decorated
    return paramed_decorator

# usage

class SomeClass(models.Model):
    # fields
    name = CharField(...)

    @stales_cache("SomeClass_some_key_that_depends_on_name_%(name)")
    @stales_cache("SomeClass_some_other_key_that_depends_on_name_%(name)")
    def update_name(self, new_name):
        self.name = new_name
        self.save()