def arc(self, x, y, radius, start_angle, end_angle):
        """draw arc going counter-clockwise from start_angle to end_angle"""
        self._add_instruction("arc", x, y, radius, start_angle, end_angle)
def arc ( self , x , y , radius , start_angle , end_angle ) : self . _add_instruction ( "arc" , x , y , radius , start_angle , end_angle )
draw arc going counter-clockwise from start_angle to end_angle