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;
	}
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;
	}
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 ; }
array key to lowercase
@param  array $array
@return array
array key to lowercase