code: def render(self, name, value, attrs=None, renderer=None):
          
          wrapped = self.widget.render(name, value, attrs, renderer)
          checkbox_name = self.clear_checkbox_name(name)
          checkbox_id = self.clear_checkbox_id(checkbox_name)
          checkbox_label = self.clear_checkbox_label
          checkbox = self.checkbox.render(
              checkbox_name,
              value == self.empty_value,
              attrs={'id': checkbox_id},
              renderer=renderer)
          return mark_safe(self.template.format(
              conditional_escape(wrapped),
              conditional_escape(checkbox_id),
              conditional_escape(checkbox_label),
              conditional_escape(checkbox)))
docs: Appends a checkbox for clearing the value (that is, setting the field
          with the ``empty_value``).