def METHOD_NAME(self, time, data, varlabel):
    # Plot variable 'varlabel' vs time
    fix, ax = plt.subplots(constrained_layout=True)
    print('Plotting {}'.format(varlabel))
    ax.METHOD_NAME(time, data)
    ax.set_xlabel('time (sec)')
    ax.set_ylabel(varlabel)
    if args.tmin < 0.0:
        tmin = None
    if args.tmax < 0.0:
        tmax = None
    ax.set_xlim(left=tmin, right=tmax)
    file_label = ''.join(s for s in varlabel if s.isalnum())
    plt.savefig('diagnostics-{}.png'.format(file_label))
    plt.clf()