code: public TokenRequestBuilder getTokenEndPoint() {
          for (Authentication apiAuth : authentications.values()) {
              if (apiAuth instanceof RetryingOAuth) {
                  RetryingOAuth retryingOAuth = (RetryingOAuth) apiAuth;
                  return retryingOAuth.getTokenRequestBuilder();
              }
          }
          return null;
      }
docs: Helper method to configure the token endpoint of the first oauth found in
  the apiAuthorizations (there should be only one)
  
  @return Token request builder