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 because if we set key_obj directly to key.name
            # then cache will be 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