docs: function(exception, options = {}) {
          const html = formatExceptionLines(exception, options, function({ line, type }) {
              line = escapeHtml(line);
  
              const style = options.inlineStyle
                  ? `style='${HTML_INLINE_STYLES[type] || ''}'`
                  : `class=${type}`;
  
              // Use inline styles, since email doesn't support style sheets.
              switch (type) {
                  case HEADER:
                      return `<h2 ${style}>${line}</h2>`;
                  default:
                      return `<span ${style}>${line}</span><br />`;
              }
          });
  
          const style = options.inlineStyle ? "style='font-family: monospace'" : "class='exception'";
          return `<div ${style}>${html}</div>`;
      }