docs: def render(self, template: str, **vars) -> str:
          """
          Render the named template.
  
          The current context will be available to the template as the ``ctx`` variable.
  
          :param template: name of the template file
          :param vars: extra template variables
          :return: the rendered results
  
          """
          vars.setdefault('ctx', self._ctx)
          return self._renderer.render(template, **vars)