code: func (ct *ClaimTree) Find(id *identity.ID, mustActive bool) (*apitypes.PublicKeySegment, error) {
  	for _, pks := range ct.PublicKeys {
  		if *pks.PublicKey.ID == *id {
  			if mustActive && pks.Revoked() {
  				continue
  			}
  
  			return &pks, nil
  		}
  	}
  
  	return nil, ErrKeyNotFound
  }
docs: // Find returns the PublicKeySegment for the given PublicKeyID. Accepts a
  // boolean for indicating whether or not to enforce that the key must be
  // active.
  //
  // If a key segment could not be found an error is returned.