public function setMode($arg) {
        $this->mode = strtolower($arg) == self::LIVE ? self::LIVE : self::SANDBOX;
        return $this;
    }
public function setMode($arg) {
        $this->mode = strtolower($arg) == self::LIVE ? self::LIVE : self::SANDBOX;
        return $this;
    }
public function setMode ( $ arg ) { $ this -> mode = strtolower ( $ arg ) == self :: LIVE ? self :: LIVE : self :: SANDBOX ; return $ this ; }
IS TEST OR LIVE
@param string $arg
@return $this
IS TEST OR LIVE