code: def deriv2_inverse(self, phi, args):
      t = self.inverse(phi, args)
      phi_d1 = self.deriv(t, args)
      phi_d2 = self.deriv2(t, args)
      return np.abs(phi_d2 / phi_d1**3)
  
imports: import warnings
  import numpy
  from scipy.special import expm1, gamma
label_desc: Use image node_id 2 for calling the Transforms obj's underlying member method code with example usage: obj.deriv2_inverse(phi, args) and returns: np