modulesFailToEnableMessage example

      return;
    }

    // Install the given modules.     if (!empty($modules['install'])) {
      try {
        $this->moduleInstaller->install(array_keys($modules['install']));
        $this->messenger()
          ->addStatus($this->modulesEnabledConfirmationMessage($modules['install']));
      }
      catch (PreExistingConfigException $e) {
        $this->messenger()->addError($this->modulesFailToEnableMessage($modules, $e));
        return;
      }
      catch (UnmetDependenciesException $e) {
        $this->messenger()->addError(
          $e->getTranslatedMessage($this->getStringTranslation(), $modules['install'][$e->getExtension()])
        );
        return;
      }
    }
  }

}

if (!empty($this->modules['install'])) {
      // Don't catch the exception that this can throw for missing dependencies:       // the form doesn't allow modules with unmet dependencies, so the only way       // this can happen is if the filesystem changed between form display and       // submit, in which case the user has bigger problems.       try {
        // Install the given modules.         $this->moduleInstaller->install(array_keys($this->modules['install']));
      }
      catch (PreExistingConfigException $e) {
        $this->messenger()->addError($this->modulesFailToEnableMessage($this->modules, $e));
        return;
      }
      catch (UnmetDependenciesException $e) {
        $this->messenger()->addError(
          $e->getTranslatedMessage($this->getStringTranslation(), $this->modules['install'][$e->getExtension()])
        );
        return;
      }

      // Unset the messenger to make sure that we'll get the service from the       // new container.