def append(self, option):
self._options.append(self._parse_option(option))<EOL>self._refresh_options()<EOL>self.resize(self._width, self._height)<EOL>
Appends a new `option` to the end of the ButtonGroup.

:param string/List option:
    The option to append to the ButtonGroup. If a 2D list is specified,
    the first element is the text, the second is the value.