code: @Restricted(NoExternalUse.class)
      public User createAccountFromSetupWizard(StaplerRequest req) throws IOException, AccountCreationFailedException {
          checkPermission(Jenkins.ADMINISTER);
          SignupInfo si = validateAccountCreationForm(req, false);
          if (!si.errors.isEmpty()) {
              String messages = getErrorMessages(si);
              throw new AccountCreationFailedException(messages);
          } else {
              return createAccount(si);
          }
      }
docs: Creates a user account. Intended to be called from the setup wizard.
  Note that this method does not check whether it is actually called from
  the setup wizard. This requires the {@link Jenkins#ADMINISTER} permission.
  
  @param req the request to retrieve input data from
  @return the created user account, never null
  @throws AccountCreationFailedException if account creation failed due to invalid form input