code: public function renderCallStack($exception)
      {
          $out = '<ul>';
          $out .= $this->renderCallStackItem($exception->getFile(), $exception->getLine(), null, null, [], 1);
          for ($i = 0, $trace = $exception->getTrace(), $length = count($trace); $i < $length; ++$i) {
              $file = !empty($trace[$i]['file']) ? $trace[$i]['file'] : null;
              $line = !empty($trace[$i]['line']) ? $trace[$i]['line'] : null;
              $class = !empty($trace[$i]['class']) ? $trace[$i]['class'] : null;
              $function = null;
              if (!empty($trace[$i]['function']) && $trace[$i]['function'] !== 'unknown') {
                  $function = $trace[$i]['function'];
              }
              $args = !empty($trace[$i]['args']) ? $trace[$i]['args'] : [];
              $out .= $this->renderCallStackItem($file, $line, $class, $function, $args, $i + 2);
          }
          $out .= '</ul>';
          return $out;
      }
docs: Renders call stack.
  @param \Exception|\ParseError $exception exception to get call stack from
  @return string HTML content of the rendered call stack.
  @since 2.0.12