laravel5.1 权限管理（使用romanbican/roles）

我在User.php中

use Bican\Roles\Traits\HasRoleAndPermission;
use Bican\Roles\Contracts\HasRoleAndPermission as HasRoleAndPermissionContract;

class User extends Model implements AuthenticatableContract,
                                    AuthorizableContract,
                                    CanResetPasswordContract,
                                    HasRoleAndPermissionContract
{
    use Authenticatable, Authorizable, CanResetPassword, HasRoleAndPermission;

报错：Trait method can has not been applied, because there are collisions with other trait methods on App\\User

请问是不能有AuthorizableContract这个吗（官方没写这个， 但是教程有这个也么可有报错, 我去掉这个AuthorizableContract就不冲突了）
请问这个怎么解决