<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def plotXYCatalog(self, **kwargs):
 """ 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`. """

        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'])