code: def get_error_traceback(self):
          
          try:
              error_page = self.get_elm(class_name='error-page')
              traceback = error_page.get_elm(class_name='traceback')
          except NoSuchElementException:
              pass
          else:
              return traceback.text
docs: Method returning traceback of error page.
  
          By default it find element with class ``error-page`` and returns text
          of element with class ``traceback``. You can change this method
          accordingly to your app.