docs: function (registrationRequest, cb) {
              if (registrationRequest.$.password) {
                  var ret = {
                      providerUserId: registrationRequest.get(this.$.usernameField),
                      authenticationData: this.createAuthenticationData(registrationRequest.$.password)
                  };
                  cb(null, ret);
              } else {
                  cb("No password set");
              }
          }