code: def open_in_browser(self, session, output_filename=None):
          
          if output_filename is None:
              output_file = tempfile.NamedTemporaryFile(suffix='.html', delete=False)
              output_filename = output_file.name
              with codecs.getwriter('utf-8')(output_file) as f:
                  f.write(self.render(session))
          else:
              with codecs.open(output_filename, 'w', 'utf-8') as f:
                  f.write(self.render(session))
  
          from pyinstrument.vendor.six.moves import urllib
          url = urllib.parse.urlunparse(('file', '', output_filename, '', '', ''))
          webbrowser.open(url)
          return output_filename
docs: Open the rendered HTML in a webbrowser.
  
          If output_filename=None (the default), a tempfile is used.
  
          The filename of the HTML file is returned.