protected function get_class_prefix( $id, $check = true ) {
		if ( strpos( $id, '\\' ) !== false && $id[0] !== '\\' ) {
			$class = '\\' . $id;

			if ( $check ) {
				return isset( $this->classes[$class] ) ? $class : $id;
			}

			return $class;
		}

		return $id;
	}