code: def plot_border(mask, should_plot_border, units, kpc_per_arcsec, pointsize, zoom_offset_pixels):
      
      if should_plot_border and mask is not None:
  
          plt.gca()
          border_pixels = mask.masked_grid_index_to_pixel[mask.border_pixels]
  
          if zoom_offset_pixels is not None:
              border_pixels -= zoom_offset_pixels
  
          border_arcsec = mask.grid_pixels_to_grid_arcsec(grid_pixels=border_pixels)
          border_units = convert_grid_units(array=mask, grid_arcsec=border_arcsec, units=units,
                                            kpc_per_arcsec=kpc_per_arcsec)
  
          plt.scatter(y=border_units[:,0], x=border_units[:,1], s=pointsize, c='y')
docs: Plot the borders of the mask or the array on the figure.
  
      Parameters
      -----------t.
      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.
      should_plot_border : bool
          If a mask is supplied, its borders pixels (e.g. the exterior edge) is plotted if this is *True*.
      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.
      border_pointsize : int
          The size of the points plotted to show the borders.