final public static function validatePresence (array $requiredFields=[], string $option=NULL) : bool
	{
		$option 			= static::checkGlobal($option);
		$fieldsWithError 	= "";
		foreach ($requiredFields as $field):
			if (!isset($option[$field]) || !static::hasValue($option[$field])) 
				$fieldsWithError .= "'".fieldNameAsText($field)."', ";
		endforeach;
		static::setError($fieldsWithError);
		return static::checkError();
	}