docs: def render(self, name, value, attrs=None, **kwargs):
          """
          Extend base class's `render` method by appending
          javascript inline text to html output.
          """
          output = super(Select2Mixin, self).render(
              name, value, attrs=attrs, **kwargs)
          id_ = attrs['id']
          output += self.render_js_code(
              id_, name, value, attrs=attrs, **kwargs)
          return mark_safe(output)