code: def draw_pnl(ax, df):
      """
      Draw p&l line on the chart.
  
      """
      ax.clear()
      ax.set_title("Performance")
      index = df.index.unique()
      dt = index.get_level_values(level=0)
      pnl = index.get_level_values(level=4)
      ax.plot(
          dt,
          pnl,
          "-",
          color="green",
          linewidth=1.0,
          label="Performance",
      )
  
      def perc(val):
          return "{:2f}".format(val)
  
      ax.format_ydata = perc
  
      set_legend(ax)
      format_ax(ax)
  
file_path: catalyst/catalyst/exchange/utils/live_chart_utils.py
imports: import matplotlib.dates
  import pandas
  from catalyst.exchange.exchange_errors import MismatchingQuoteCurrenciesExchanges
label_desc: Use image node_id 3 for calling a global function with example usage: draw_pnl(ax, df) and returns: str