code: def draw_circle(setter, x0, y0, r, color=None):
      
      f = 1 - r
      ddF_x = 1
      ddF_y = -2 * r
      x = 0
      y = r
  
      setter(x0, y0 + r, color)
      setter(x0, y0 - r, color)
      setter(x0 + r, y0, color)
      setter(x0 - r, y0, color)
  
      while x < y:
          if f >= 0:
              y -= 1
              ddF_y += 2
              f += ddF_y
          x += 1
          ddF_x += 2
          f += ddF_x
  
          setter(x0 + x, y0 + y, color)
          setter(x0 - x, y0 + y, color)
          setter(x0 + x, y0 - y, color)
          setter(x0 - x, y0 - y, color)
          setter(x0 + y, y0 + x, color)
          setter(x0 - y, y0 + x, color)
          setter(x0 + y, y0 - x, color)
          setter(x0 - y, y0 - x, color)
docs: Draws a circle at point x0, y0 with radius r of the specified RGB color