code: public function process( File $phpcsFile, $stackPtr ) {
  
  		$tokens = $phpcsFile->getTokens();
  
  		if ( preg_match( self::IFRAME_REGEX, $tokens[ $stackPtr ]['content'], $matches ) > 0 ) {
  			$phpcsFile->addError(
  				'Usage of the iframe HTML element is prohibited. Found: %s',
  				$stackPtr,
  				'Found',
  				array( $matches[1] )
  			);
  		}
  	}
docs: Processes this test, when one of its tokens is encountered.
  
  @param \PHP_CodeSniffer\Files\File $phpcsFile The PHP_CodeSniffer file where the
  token was found.
  @param int                         $stackPtr  The position of the current token
  in the stack.
  
  @return void