static public function toLowerCaseKey(array $array)
	{
	    $res = [];
	    if ($array) {
	        foreach ($array as $k  => $v) {
	            if (is_array($v)) {
	                $v = static::toLowerCaseKey($v);
	            }
	            $res[strtolower($k)] = $v;
	        }
	    }
	    return $res;
	}