code: def plot_mask(mask, units, kpc_per_arcsec, pointsize, zoom_offset_pixels):
      
  
      if mask is not None:
  
          plt.gca()
          edge_pixels = mask.masked_grid_index_to_pixel[mask.edge_pixels] + 0.5
          if zoom_offset_pixels is not None:
              edge_pixels -= zoom_offset_pixels
          edge_arcsec = mask.grid_pixels_to_grid_arcsec(grid_pixels=edge_pixels)
          edge_units = convert_grid_units(array=mask, grid_arcsec=edge_arcsec, units=units,
                                            kpc_per_arcsec=kpc_per_arcsec)
  
          plt.scatter(y=edge_units[:,0], x=edge_units[:,1], s=pointsize, c='k')
docs: Plot the mask of the array on the figure.
  
      Parameters
      -----------
      mask : ndarray of data.array.mask.Mask
          The mask applied to the array, the edge of which is plotted as a set of points over the plotted array.
      units : str
          The units of the y / x axis of the plots, in arc-seconds ('arcsec') or kiloparsecs ('kpc').
      kpc_per_arcsec : float or None
          The conversion factor between arc-seconds and kiloparsecs, required to plot the units in kpc.
      pointsize : int
          The size of the points plotted to show the mask.