code: def plot_pressure(self, p, plot_range=None):
          
          # PLOT PRESSURE
          if not plot_range:
              plot_range = [970, 1030, 2]
          self.ax4 = fig.add_subplot(4, 1, 4, sharex=self.ax1)
          self.ax4.plot(self.dates, p, 'm', label='Mean Sea Level Pressure')
          self.ax4.set_ylabel('Mean Sea\nLevel Pressure\n(mb)', multialignment='center')
          self.ax4.set_ylim(plot_range[0], plot_range[1], plot_range[2])
  
          axtwin = self.ax4.twinx()
          axtwin.set_ylim(plot_range[0], plot_range[1], plot_range[2])
          axtwin.fill_between(self.dates, p, axtwin.get_ylim()[0], color='m')
          axtwin.xaxis.set_major_formatter(mpl.dates.DateFormatter('%d/%H UTC'))
  
          self.ax4.legend(loc='upper center', bbox_to_anchor=(0.5, 1.2), prop={'size': 12})
          self.ax4.grid(b=True, which='major', axis='y', color='k', linestyle='--',
                        linewidth=0.5)
docs: Required input:
              P: Mean Sea Level Pressure (hPa)
          Optional Input:
              plot_range: Data range for making figure (list of (min,max,step))