code: func getNonRevocationProver(algorithm RevocationAlgorithm) (nonRevokedProver, error) {
  	switch algorithm {
  	case ALG_NO_REVOCATION:
  		return &nopNonRevokedProver{}, nil
  	default:
  		// unknown revocation algorithm
  		return nil, errors.Errorf("unknown revocation algorithm %d", algorithm)
  	}
  }
docs: // getNonRevocationProver returns the nonRevokedProver bound to the passed revocation algorithm