human
What is a the Python code you requested given the following:
Complete the below
def cache_relation(descriptor, timeout=None):

    ''''Adds utility methods to a model to obtain related
    model instances via a cache.'
    '''
assistant
#Here is the Python code you requested.
    rel = descriptor.related
    related_name = ('%s_cache' % rel.field.related_query_name())
    @property
    def get(self):
        '\n                                Returns    the    cached    value    of    the    related    model    if    found\n                                in    the    cache.    Otherwise    gets    and    caches    the    related    model.\n                                '
        try:
            return getattr(self, descriptor.cache_name)
        except AttributeError:
            pass
        try:
            return getattr(self, ('_%s_cache' % related_name))
        except AttributeError:
            pass
        instance = get_instance(rel.model, self.pk, timeout)
        setattr(self, ('_%s_cache' % related_name), instance)
        return instance
    setattr(rel.parent_model, related_name, get)
    def clear(self):
        '\n                                Clears    the    cache    of    all    related    models    of    self.\n                                '
        delete_instance(rel.model, self)
    @classmethod
    def clear_pk(cls, *instances_or_pk):
        '\n                                Clears    the    cache    of    all    related    models    of\n                                the    provided    instances_or_pk.\n                                '
        delete_instance(rel.model, *instances_or_pk)
    def clear_cache(sender, instance, *args, **kwargs):
        '\n                                Clears    the    cache    of    all    related    models    of    the\n                                given    instance.\n                                '
        delete_instance(rel.model, instance)
    setattr(rel.parent_model, ('%s_clear' % related_name), clear)
    setattr(rel.parent_model, ('%s_clear_pk' % related_name), clear_pk)
    post_save.connect(clear_cache, sender=rel.model, weak=False)
    post_delete.connect(clear_cache, sender=rel.model, weak=False)