code: public static ChallengeFetcher fetcher(final String pathServiceSid, 
                                             final String pathIdentity, 
                                             final String pathFactorSid, 
                                             final String pathSid) {
          return new ChallengeFetcher(pathServiceSid, pathIdentity, pathFactorSid, pathSid);
      }
docs: Create a ChallengeFetcher to execute fetch.
  
  @param pathServiceSid Service Sid.
  @param pathIdentity Unique identity of the Entity
  @param pathFactorSid Factor Sid.
  @param pathSid A string that uniquely identifies this Challenge, or `latest`.
  @return ChallengeFetcher capable of executing the fetch