final public static function validateUserId (array $fields=[], string $field) : bool
	{
		$fieldsWithError 	= "";
		$field 				= static::checkGlobal($field);
		foreach ($fields as $fieldName => $format)
		{
			$value = static::setValueNull($field[$fieldName]);
			if ($value !== NULL)
			{
				if (!static::formatMatch($value, $format))
					$fieldsWithError .= "'".fieldNameAsText($fieldName)."', ";
			}
		}
		static::setError($fieldsWithError);
		return static::checkError();
	}