code: def _addPolylineToElements(self):
          
          if (len(self._pointsOfPolyline) > 1):
              s = ''
              for point in self._pointsOfPolyline:
                  s += str(point) + ' '#str(point.x) + ',' + str(point.y) + ' '
              p = Polyline(s)
              p.set_style('fill:' + self.fill + '; stroke:' + self.stroke + '; stroke-width:' + self.strokeWidth) 
              self._svgElements.append(p)
          self._pointsOfPolyline = []
          self._pointsOfPolyline.append(Vector(self._position.x, self._position.y))
docs: Creates a new Polyline element that will be used for future movement/drawing. 
          The old one (if filled) will be stored on the movement stack.