public function parse( $template_file )
    {
        if ( file_exists( $template_file ) ) {
            $content = file_get_contents($template_file);

            foreach ( $this->vars as $key => $value ) {
                if ( is_array( $value ) ) {
                    $content = $this->parsePair($key, $value, $content);
                } else {
                    $content = $this->parseSingle($key, (string) $value, $content);
                }
            }

            return $content;
        } else {
            exit( '<h1>Template error</h1>' );
        }
    }