code: def plotProgenitor(self,d1='x',d2='z',*args,**kwargs):
          
          tts= self._progenitor._orb.t[self._progenitor._orb.t \
                                            < self._trackts[self._nTrackChunks-1]]
          obs= [self._R0,0.,self._Zsun]
          obs.extend(self._vsun)
          phys= kwargs.pop('scaleToPhysical',False)
          tx= self._parse_progenitor_dim(d1,tts,ro=self._ro,vo=self._vo,
                                         obs=obs,phys=phys)
          ty= self._parse_progenitor_dim(d2,tts,ro=self._ro,vo=self._vo,
                                         obs=obs,phys=phys)
          bovy_plot.bovy_plot(tx,ty,*args,
                              xlabel=_labelDict[d1.lower()],
                              ylabel=_labelDict[d2.lower()],
                              **kwargs)
          return None
docs: NAME:
  
             plotProgenitor
  
          PURPOSE:
  
             plot the progenitor orbit
  
          INPUT:
  
             d1= plot this on the X axis ('x','y','z','R','phi','vx','vy','vz','vR','vt','ll','bb','dist','pmll','pmbb','vlos')
  
             d2= plot this on the Y axis (same list as for d1)
  
             scaleToPhysical= (False), if True, plot positions in kpc and velocities in km/s
  
             bovy_plot.bovy_plot args and kwargs
  
          OUTPUT:
  
             plot to output device
  
          HISTORY:
  
             2013-12-09 - Written - Bovy (IAS)