code: def der(self, coords):
      x, y = coords
      dfdx = (
          2.0 * (1.5 - x + x * y) * (-1.0 + y)
          + 2.0 * (2.25 - x + x * y**2) * (-1.0 + y**2)
          + 2.0 * (2.625 - x + x * y**3) * (-1.0 + y**3)
      )
      dfdy = (
          2.0 * (1.5 - x + x * y) * (x)
          + 2.0 * (2.25 - x + x * y**2) * (2.0 * y * x)
          + 2.0 * (2.625 - x + x * y**3) * (3.0 * x * y**2)
      )
      return np.array([dfdx, dfdy])
  
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 2 for calling the Beale obj's underlying member method code with example usage: obj.der(coords) and returns: np