code: func New(challengeTypes map[string]bool) (*AuthorityImpl, error) {
  
  	pa := AuthorityImpl{
  		log:               blog.Get(),
  		enabledChallenges: challengeTypes,
  		// We don't need real randomness for this.
  		pseudoRNG: rand.New(rand.NewSource(99)),
  	}
  
  	return &pa, nil
  }
docs: // New constructs a Policy Authority.