Mage2\User\Controllers\Admin\RoleController::_saveRolePermissions PHP Method

    private function _saveRolePermissions($request, $role)
    {
        $permissionIds = [];
        if (count($request->get('permissions')) > 0) {
            //$permissionIds = Collection::make([]);
            foreach ($request->get('permissions') as $key => $value) {
                //save it into db
                if ($value != 1) {
                    continue;
                }
                $permissions = explode(',', $key);
                foreach ($permissions as $permissionName) {
                    if (null === ($permissionModel = Permission::getPermissionByName($permissionName))) {
                        $permissionModel = Permission::create(['name' => $permissionName]);
                    }
                    $permissionIds[] = $permissionModel->id;
                }
            }
        }
        $ids = array_unique($permissionIds);
        $role->permissions()->sync($ids);
        return $this;
    }