static private function _checkData($arr, $v) 
    {
        foreach($arr as $key=>$value)
        {
            if(!is_array($key)) { 
                if ($res = static::_checkString($key, $v)) {
                    return $res;
                }
            } else { 
                if ($res = static::_checkData($key, $v)) {
                    return $res;
                }
            }
            
            if(!is_array($value)) { 
                if ($res = static::_checkString($value, $v)) {
                    return $res;
                }
            } else { 
                if ($res = static::_checkData($value, $v)) {
                    return $res;
                }
            }
        }
        
        return null;
    }
static private function _checkData($arr, $v) 
    {
        foreach($arr as $key=>$value)
        {
            if(!is_array($key)) { 
                if ($res = static::_checkString($key, $v)) {
                    return $res;
                }
            } else { 
                if ($res = static::_checkData($key, $v)) {
                    return $res;
                }
            }
            
            if(!is_array($value)) { 
                if ($res = static::_checkString($value, $v)) {
                    return $res;
                }
            } else { 
                if ($res = static::_checkData($value, $v)) {
                    return $res;
                }
            }
        }
        
        return null;
    }
static private function _checkData ( $ arr , $ v ) { foreach ( $ arr as $ key => $ value ) { if ( ! is_array ( $ key ) ) { if ( $ res = static :: _checkString ( $ key , $ v ) ) { return $ res ; } } else { if ( $ res = static :: _checkData ( $ key , $ v ) ) { return $ res ; } } if ( ! is_array ( $ value ) ) { if ( $ res = static :: _checkString ( $ value , $ v ) ) { return $ res ; } } else { if ( $ res = static :: _checkData ( $ value , $ v ) ) { return $ res ; } } } return null ; }
check data, if safe return null, if has unsafe string return unsafe value

@param  mixed $arr array|string
@param  array $v

@return string
check data if safe return null if has unsafe string return unsafe value