code: public function register() {
  		// Build the regex to be used only once.
  		$regex_parts = array();
  
  		foreach ( $this->attribute_blacklist as $key => $values ) {
  			$values        = array_map( 'preg_quote', $values, array_fill( 0, count( $values ), '`' ) );
  			$values        = implode( '|', $values );
  			$regex_parts[] = sprintf( self::REGEX_ATTR_TEMPLATE, preg_quote( $key, '`' ), $values );
  		}
  
  		$this->favicon_regex = sprintf( self::REGEX_TEMPLATE, implode( '|', $regex_parts ) );
  
  		return Tokens::$textStringTokens;
  	}
docs: Returns an array of tokens this test wants to listen for.
  
  @return array