    def _find_option(self, search_value):
        """
        Internal function called by the BaseListBox to do a text search on user input.

        :param search_value: The string value to search for in the list.
        :return: The value of the matching option (or None if nothing matches).
        """
Internal function called by the BaseListBox to do a text search on user input.

:param search_value: The string value to search for in the list.
:return: The value of the matching option (or None if nothing matches).
asciimatics/widgets/baselistbox.py