code: def add_option(self, value, text, selected=False):
          
          option = {"value": value, "text": text, "selected":selected}
          self.options += [option]
          if selected:
              self.selected_options += [option]
              self._value.append(value)
              if self._persist_value:
                  self.settings.store_value("selected_options", self.selected_options)
docs: Add option to select
  
          :param value: The value that the option represent.
  
          :param text: The text that should be displayer in dropdown
  
          :param selected: True if the option should be the default value.