code: def mandel(x, y, max_iters):
      
      i = 0
      c = complex(x,y)
      z = 0.0j
      for i in range(max_iters):
          z = z*z + c
          if (z.real*z.real + z.imag*z.imag) >= 4:
              return i
  
      return 255
docs: Given the real and imaginary parts of a complex number,
      determine if it is a candidate for membership in the Mandelbrot
      set given a fixed number of iterations.