How to use the mc3.plots function in mc3

def test_subplotter():
    rect = [0.1, 0.1, 0.9, 0.9]
    margin = 0.1
    ipan = 1
    nx = 2
    axis = mp.subplotter(rect, margin, ipan, nx)

if savefile is not None:
      unpickables = ['dynesty_sampler']
      unpickables = np.intersect1d(unpickables, list(output.keys()))
      tmp_outputs = {key: output.pop(key) for key in unpickables}
      np.savez(savefile, **output)
      output.update(tmp_outputs)
      log.msg("'{:s}'".format(savefile), indent=2)

  if plots:
      # Extract filename from savefile or default to sampler:
      fname = sampler if savefile is None else os.path.splitext(savefile)[0]
      # Include bestp in posterior plots:
      best_freepars = output['bestp'][ifree] if showbp else None

      # Trace plot:
      mp.trace(output['posterior'], zchain=output['zchain'],
          burnin=output['burnin'], pnames=texnames[ifree],
          savefile=fname+"_trace.png")
      log.msg("'{:s}'".format(fname+"_trace.png"), indent=2)
      # Pairwise posteriors:
      mp.pairwise(posterior, pnames=texnames[ifree], bestp=best_freepars,
          savefile=fname+"_pairwise.png")
      log.msg("'{:s}'".format(fname+"_pairwise.png"), indent=2)
      # Histograms:
      mp.histogram(posterior, pnames=texnames[ifree], bestp=best_freepars,
          savefile=fname+"_posterior.png",
          quantile=0.683, pdf=pdf, xpdf=xpdf)
      log.msg("'{:s}'".format(fname+"_posterior.png"), indent=2)
      # RMS vs bin size:
      if rms:
          RMS, RMSlo, RMShi, stderr, bs = ms.time_avg(output['best_model']-data)
          mp.rms(bs, RMS, stderr, RMSlo, RMShi, binstep=len(bs)//500+1,