public function allow()
    {
        $roleNames = func_get_args();

        // Flatten array to allow array inputs
        $roleNames = Core::array_flatten($roleNames);

        foreach ($roleNames as $role) {

            if (!in_array($role, $this->allowedRoles)) {
                $this->allowedRoles[] = $role;
            }
        }

        return $this;
    }