docs: def formfield(self, **kwargs):
          """
          Apply the widget class defined by the
          ``RICHTEXT_WIDGET_CLASS`` setting.
          """
          default = kwargs.get("widget", None) or AdminTextareaWidget
          if default is AdminTextareaWidget:
              from yacms.conf import settings
              richtext_widget_path = settings.RICHTEXT_WIDGET_CLASS
              try:
                  widget_class = import_dotted_path(richtext_widget_path)
              except ImportError:
                  raise ImproperlyConfigured(_("Could not import the value of "
                                               "settings.RICHTEXT_WIDGET_CLASS: "
                                               "%s" % richtext_widget_path))
              kwargs["widget"] = widget_class()
          kwargs.setdefault("required", False)
          formfield = super(RichTextField, self).formfield(**kwargs)
          return formfield