protected function isInterface(PHP_CodeSniffer_File $phpcsFile) {
        $checkFile = "". $phpcsFile->getFilename();
        if (isset($this->isFileInterface[$checkFile])) {
            return (bool) $this->isFileInterface[$checkFile];
        }

        $interface = $phpcsFile->findNext(T_INTERFACE, 0);

        return $this->isFileInterface[$checkFile] = (bool)(empty($interface) == false);
    }