Render with a label inside the bar graph.

def _render_internal_label(self):
        ''' Render with a label inside the bar graph. '''
        ncc = self._num_complete_chars
        bar = self._lbl.center(self.iwidth)
        cm_chars = self._comp_style(bar[:ncc])
        em_chars = self._empt_style(bar[ncc:])
        return f'{self._first}{cm_chars}{em_chars}{self._last}'