public static function buildNormalRelation($user, $other)
    {
        $relation = static::buildRelation($user, $other);
        if (!$relation) {
            return null;
        }
        if ($relation->relationType == static::$relationMutual) {
            $relation->setMutualType(static::$mutualTypeNormal);
        }
        return $relation;
    }