code: def get_arrowhead(self, direction, x, y, end):
          
          if direction == "left":
              pos1, pos2, pos3 = (x, x - self.arrow_width + 2, x + self.arrow_width - 2)
          else:
              pos1, pos2, pos3 = (
                  end,
                  end + self.arrow_width - 2,
                  end - self.arrow_width + 2,
              )
          arrowhead = (
              pos1,
              y + 2,
              pos2,
              y - self.arrow_width,
              pos3,
              y - self.arrow_width,
          )
          return "M{},{} L{},{} {},{}".format(*arrowhead)
docs: Render individual arrow head.
  
          direction (unicode): Arrow direction, 'left' or 'right'.
          x (int): X-coordinate of arrow start point.
          y (int): Y-coordinate of arrow start and end point.
          end (int): X-coordinate of arrow end point.
          RETURNS (unicode): Definition of the arrow head path ('d' attribute).