private function getRememberDirectiveExpiry() {
		// if the user is currently signed in
		if ($this->isLoggedIn()) {
			// determine the selector of any currently existing remember directive
			$existingSelector = $this->getRememberDirectiveSelector();

			// if there is currently a remember directive whose selector we have just retrieved
			if (isset($existingSelector)) {
				// fetch the expiry date for the given selector
				$existingExpiry = $this->db->selectValue(
					'SELECT expires FROM ' . $this->makeTableName('users_remembered') . ' WHERE selector = ? AND user = ?',
					[
						$existingSelector,
						$this->getUserId()
					]
				);

				// if an expiration date has been found
				if (isset($existingExpiry)) {
					// return the date
					return (int) $existingExpiry;
				}
			}
		}

		return null;
	}