Insert a new `option` in the Combo at `index`.

        :param int option:
            The index of where to insert the option.

        :param string option:
            The option to insert into to the Combo.

def insert(self, index, option):
        """
        Insert a new `option` in the Combo at `index`.

        :param int option:
            The index of where to insert the option.

        :param string option:
            The option to insert into to the Combo.
        """
        option = str(option)
        self._options.insert(index, option)
        # if this is the first option, set it.
        if len(self._options) == 1:
            self.value = option

        self._refresh_options()