code: def triangle(self, x1, y1, x2, y2, x3, y3, color="black", outline=False, outline_color="black"):
          
          return self.polygon(
              x1, y1, x2, y2, x3, y3, 
              color=color, 
              outline=outline, 
              outline_color=outline_color)
docs: Draws a triangle between 3 points
  
          :param int x1:
              The x position of the starting point.
  
          :param int y1:
              The y position of the starting point.
  
          :param int x2:
              The x position of the middle point.
  
          :param int y2:
              The y position of the middle point.
  
          :param int x3:
              The x position of the end point.
  
          :param int y3:
              The y position of the end point.
  
          :param str color:
              The color of the shape. Defaults to `"black"`.
  
          :param int outline:
              `0` or `False` is no outline. `True` or value > 1 sets an outline. Defaults to `False`.
  
          :param str outline_color:
              The color of the outline. Defaults to `"black"`.
  
          :return:
              The id of the shape.