new_contents: """
  Display and plotting tools module.
  """
  import astropy.io.fits as fits
  import astropy.visualization as viz
  import astropy.wcs
  import matplotlib.pyplot as plt
  
  def render_fits_image(hdu, scale='asinh', cmap=plt.cm.gray,
                        xlabel='RA', ylabel='Dec', title=None):
      "Use matplotlib and astropy to render a FITS image HDU"
      wcs = astropy.wcs.WCS(hdu.header)
      fig = plt.figure()
      axes = fig.add_subplot(111, projection=wcs)
      plt.imshow(viz.scale_image(hdu.data, scale=scale),
                 cmap=cmap, origin='lower', interpolation='none')
      plt.xlabel(xlabel)
      plt.ylabel(ylabel)
      if title is not None:
          axes.set_title(title)
      return fig
  
subject: add Display module