code: def plot_origin(array, origin, units, kpc_per_arcsec, zoom_offset_arcsec):
      
      if origin is not None:
  
          origin_grid = np.asarray(origin)
  
          if zoom_offset_arcsec is not None:
              origin_grid -= zoom_offset_arcsec
  
          origin_units = convert_grid_units(array=array, grid_arcsec=origin_grid, units=units,
                                            kpc_per_arcsec=kpc_per_arcsec)
          plt.scatter(y=origin_units[0], x=origin_units[1], s=80, c='k', marker='x')
docs: Plot the (y,x) origin ofo the array's coordinates as a 'x'.
      
      Parameters
      -----------
      array : data.array.scaled_array.ScaledArray
          The 2D array of data which is plotted.
      origin : (float, float).
          The origin of the coordinate system of the array, which is plotted as an 'x' on the image if input.
      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.