code: func WBBVerify(pk *FP256BN.ECP2, sig *FP256BN.ECP, m *FP256BN.BIG) error {
  	if pk == nil || sig == nil || m == nil {
  		return errors.Errorf("Weak-BB signature invalid: received nil input")
  	}
  	// Set P = pk * g2^m
  	P := FP256BN.NewECP2()
  	P.Copy(pk)
  	P.Add(GenG2.Mul(m))
  	P.Affine()
  	// check that e(sig, pk * g2^m) = e(g1, g2)
  	if !FP256BN.Fexp(FP256BN.Ate(P, sig)).Equals(GenGT) {
  		return errors.Errorf("Weak-BB signature is invalid")
  	}
  	return nil
  }
docs: // WBBVerify verifies a weak Boneh-Boyen signature sig on message m with public key pk