def load_foreign(object_list, foreign_keys=None):

    """

    Load foreign key objects which could be null

    """

    if not object_list:

        return object_list

    object = object_list[0]

    from django.db.models.fields.related import ForeignKey

    if foreign_keys is None:

        foreign_keys = []

        for field in object._meta.fields:

            if isinstance(field, ForeignKey):

                foreign_keys.append(field.name)

    for x in xrange(len(foreign_keys)):

        key = object._meta.get_field(foreign_keys[x])

        foreign_keys[x] = key

        fk_ids = [getattr(x, '%s_id' % key.name) for x in object_list]

        fk_ids = filter(None, fk_ids)

        key.cache = dict([(x.pk, x) for x in key.rel.to.objects.filter(pk__in=fk_ids)])



    for obj in object_list:

        for key in foreign_keys:

            key_obj = key.cache.get(getattr(obj, '%s_id' % key.name), None)

            # Use cache_name becouse if we set key_obj directly to key.name

            # then cache will erased and in next call to foreign key related object will

            # be loaded from DB

            # see django.db.models.fields.related.ReverseSingleRelatedObjectDescriptor for details

            setattr(obj, key.get_cache_name(), key_obj)

    return object_list