code: def plotXYCatalog(self, **kwargs):
          
          try:
              from matplotlib import pyplot as pl
          except:
              pl = None
  
          if pl is not None: # If the pyplot package could be loaded...
              pl.clf()
              pars = kwargs.copy()
  
              if 'marker' not in pars:
                  pars['marker'] = 'b+'
  
              if 'cmap' in pars:
                  pl_cmap = pars['cmap']
                  del pars['cmap']
              else:
                  pl_cmap = 'summer'
              pl_vmin = None
              pl_vmax = None
              if 'vmin' in pars:
                  pl_vmin = pars['vmin']
                  del pars['vmin']
              if 'vmax' in pars:
                  pl_vmax = pars['vmax']
                  del pars['vmax']
  
              pl.imshow(self.source,cmap=pl_cmap,vmin=pl_vmin,vmax=pl_vmax)
              pl.plot(self.xypos[0]-1,self.xypos[1]-1,pars['marker'])
docs: Method which displays the original image and overlays the positions
          of the detected sources from this image's catalog.
  
          Plotting `kwargs` that can be provided are:
  
              vmin, vmax, cmap, marker
  
          Default colormap is `summer`.