Bolt\Controller\Backend\Users::firstPost PHP Method

    private function firstPost(Request $request, Form $form)
    {
        if (!($userEntity = $this->validateUserForm($request, $form, true))) {
            return false;
        }
        $event = new AccessControlEvent($request);
        $login = $this->login()->login($userEntity->getUsername(), $form->get('password')->getData(), $event);
        $token = $this->session()->get('authentication');
        if ($login && $token) {
            $this->flashes()->clear();
            $this->flashes()->success(Trans::__('general.bolt-welcome-new-site', ['%USER%' => $userEntity->getDisplayname()]));
            $response = $this->setAuthenticationCookie($request, $this->redirectToRoute('dashboard'), (string) $token);
            return $response;
        }
        if (!$token) {
            $this->flashes()->error(Trans::__('general.phrase.error-session-data-login'));
        } else {
            $this->flashes()->error(Trans::__('general.phrase.something-went-wrong-after-first-user'));
        }
        return false;
    }