code: def Draw(self, stoplist=None, triplist=None, height=520):
      
      output = str()
      if not triplist:
        triplist = []
      if not stoplist:
        stoplist = []
  
      if not self._cache or triplist or stoplist:
        self._gheight = height
        self._tlist=triplist
        self._slist=stoplist
        self._decorators = []
        self._stations = self._BuildStations(stoplist)
        self._cache = "%s %s %s %s" % (self._DrawBox(),
                                        self._DrawHours(),
                                        self._DrawStations(),
                                        self._DrawTrips(triplist))
  
  
  
      output = "%s %s %s %s" % (self._DrawHeader(),
                                self._cache,
                                self._DrawDecorators(),
                                self._DrawFooter())
      return output
docs: Main interface for drawing the marey graph.
  
      If called without arguments, the data generated in the previous call
      will be used. New decorators can be added between calls.
  
      Args:
        # Class Stop is defined in transitfeed.py
        stoplist: [Stop, Stop, ...]
        # Class Trip is defined in transitfeed.py
        triplist: [Trip, Trip, ...]
  
      Returns:
        # A string that contain a svg/xml web-page with a marey graph.
        " <svg  width="1440" height="520" version="1.1" ... "