Laravel 5.3 ACL Using Gate Facad

Question

I am trying to implemnt ACL using Laravel Polices and Gate. Below is my code. UserPolcy:

class UserPolicy
{
    use HandlesAuthorization;

    public function isRoleAllowed(User $user, $role)
    {
        return in_array( $role , $user->getRoles());
    }
}

AuthServiceProvider:

class AuthServiceProvider extends ServiceProvider
{
    protected $policies = [
        'App\Model' => 'App\Policies\ModelPolicy',
    ];
    public function boot()
    {
        $this->registerPolicies();


        // User Policy
        foreach ( get_class_methods(new \App\Policies\UserPolicy) as $method ) {
            Gate::define($method, "App\Policies\UserPolicy@{$method}");
        }

    }
}

How I am try to access isRoleAllowed in my controller,

Gate::allows('isRoleAllowed', 'APPROVE_INVOICE')

It is always return true. It is not executing isRoleAllowed function. I don't know where I am getting wrong.