code: def plot_max_median_position_concentration(positions, ax=None, **kwargs):
      
  
      if ax is None:
          ax = plt.gca()
  
      alloc_summary = pos.get_max_median_position_concentration(positions)
      colors = ['mediumblue', 'steelblue', 'tomato', 'firebrick']
      alloc_summary.plot(linewidth=1, color=colors, alpha=0.6, ax=ax)
  
      ax.legend(loc='center left', frameon=True, framealpha=0.5)
      ax.set_ylabel('Exposure')
      ax.set_title('Long/short max and median position concentration')
  
      return ax
docs: Plots the max and median of long and short position concentrations
      over the time.
  
      Parameters
      ----------
      positions : pd.DataFrame
          The positions that the strategy takes over time.
      ax : matplotlib.Axes, optional
          Axes upon which to plot.
  
      Returns
      -------
      ax : matplotlib.Axes
          The axes that were plotted on.