code: public function configure(ArrayNodeDefinition $builder)
      {
          $config = $builder->children();
  
          foreach ([
              'wait_for_redirect' => [
                  'defaultValue' => 30,
                  'info' => 'The timeout (in seconds) for waiting opening a page',
              ],
              'wait_for_email' => [
                  'defaultValue' => 30,
                  'info' => 'This timeout will be used if you checking an email via IMAP',
              ],
              'email_account_strings' => [
                  'defaultValue' => '',
                  'info' => 'See detailed description in "docs/examples/EMAIL.md"',
              ],
          ] as $scalarNode => $data) {
              $config = $config->scalarNode($scalarNode)
                  ->defaultValue($data['defaultValue'])
                  ->info($data['info'])
                  ->end();
          }
  
          $config = $config->arrayNode('email_accounts')
              ->requiresAtLeastOneElement()
              ->prototype('array')
              ->children();
  
          foreach ([
              'imap' => 'IMAP url without parameters. For example: imap.gmail.com:993/imap/ssl',
              'username' => 'Login from an e-mail account',
              'password' => 'Password from an e-mail account',
          ] as $scalarNode => $info) {
              $config = $config->scalarNode($scalarNode)
                  ->isRequired()
                  ->cannotBeEmpty()
                  ->info($info)
                  ->end();
          }
  
          $config->end()->end()->end()->end();
      }
docs: {@inheritDoc}
  
  @link http://symfony.com/doc/current/components/config/definition.html
  
  @example
  Drupal\TqExtension:
  wait_for_redirect: 60
  email_account_strings: get_account_strings_for_email
  email_accounts:
  account_alias:
  imap: imap.gmail.com:993/imap/ssl
  email: example1@email.com
  password: p4sswDstr_1
  administrator:
  imap: imap.gmail.com:993/imap/ssl
  email: example2@email.com
  password: p4sswDstr_2