code: def fun(self, x):
      num = cos(sin(abs(x[0] ** 2 - x[1] ** 2))) ** 2 - 0.5
      den = (1 + 0.001 * (x[0] ** 2 + x[1] ** 2)) ** 2
      return 0.5 + num / den
  
imports: import time
  import numpy
  from numpy import sin, cos, pi, exp, sqrt, abs
  from scipy.optimize import rosen
label_desc: Use image node_id 1 for calling the Schaffer4 obj's underlying member method code with example usage: obj.fun(x) and returns: unknown