Otp::getUserLogin

public function getUserLogin()
{
	if ($this->userLogin === null && $this->userId)
	{
		$this->userLogin = BitrixMainUserTable::query()
			->addFilter('=ID', $this->getUserId())
			->addSelect('LOGIN')
			->exec()
			->fetch();

		$this->userLogin = $this->userLogin['LOGIN'];
	}

	return $this->userLogin;
}