Submission::__isset( string $property )

	public function __isset( $property ) {
		if ( 'values' === $property ) {
			return true;
		}

		if ( preg_match( '/^element_([0-9]+)_([a-z_]+)_value$/U', $property, $matches ) ) {
			$values = $this->get_element_values_data();

			if ( isset( $values[ $matches[1] ] ) && isset( $values[ $matches[1] ][ $matches[2] ] ) ) {
				return true;
			}

			return false;
		}

		return parent::__isset( $property );
	}