public function register_control($control_id, $class_name)
{
if (!class_exists($class_name)) {
return new \WP_Error('element_class_name_not_exists');
}
$instance_control = new $class_name();
if (!$instance_control instanceof Control_Base) {
return new \WP_Error('wrong_instance_control');
}
$this->_controls[$control_id] = $instance_control;
return true;
}