docs: private Session getSession(boolean isSingleton) {
  		final MailAccount mailAccount = this.mailAccount;
  		Authenticator authenticator = null;
  		if (mailAccount.isAuth()) {
  			authenticator = new UserPassAuthenticator(mailAccount.getUser(), mailAccount.getPass());
  		}
  
  		return isSingleton ? Session.getDefaultInstance(mailAccount.getSmtpProps(), authenticator) //
  				: Session.getInstance(mailAccount.getSmtpProps(), authenticator);
  	}