docs: def default_value(self):
          """ The default category when making a query
          """
          if not hasattr(self, "_default_value"):
              if self.elem_type == "select":
                  try:
                      # Get option marked "selected"
                      def_value = get_option_value(self.elem.select_one("[selected]"))
                  except AttributeError:
                      # ...or if that one doesen't exist get the first option
                      def_value = get_option_value(self.elem.select_one("option"))
  
              elif self.elem_type == "checkbox":
                  def_value = self.elem.get("value")
  
              elif self.elem_type == "radio":
                  def_value = [x for x in self.elem if x.has_attr("checked")][0].get("value")
  
              self._default_value = def_value
  
              assert def_value is not None
  
          return self._default_value