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.

def _addPolylineToElements(self):
        """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.
        """
        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))