def turn_on_selected(self):
        """
        Sets the selected modifier inside of context block.

        For example:
            >>> with theme.turn_on_selected():
            >>>     attr = theme.get('CursorBlock')

        Is the same as:
            >>> attr = theme.get('CursorBlock', selected=True)

        Is also the same as:
            >>> attr = theme.get('@CursorBlock')

        """
        # This context manager should never be nested
        assert self._selected is None

        self._selected = True
        try:
            yield
        finally:
            self._selected = None

        Sets the selected modifier inside of context block.

        For example:
            >>> with theme.turn_on_selected():
            >>>     attr = theme.get('CursorBlock')

        Is the same as:
            >>> attr = theme.get('CursorBlock', selected=True)

        Is also the same as:
            >>> attr = theme.get('@CursorBlock')

        
rtv/theme.py