function rsi(g) {
      var group = p.dataSelector(g);

      group.entry.append('path').attr('class', 'overbought');
      group.entry.append('path').attr('class', 'middle');
      group.entry.append('path').attr('class', 'oversold');
      group.entry.append('path').attr('class', 'rsi');

      rsi.refresh(g);
    }
Generic mixin used for most plots
@returns {plotMixin}