Core/Config.php
public function getPayPalCommunicationUrl($token = null, $userAction = 'continue')
    {
        return $this->getUrl() . '&cmd=_express-checkout&token=' . (string) $token . '&useraction=' . (string) $userAction;
    }
public function getPayPalCommunicationUrl($token = null, $userAction = 'continue')
    {
        return $this->getUrl() . '&cmd=_express-checkout&token=' . (string) $token . '&useraction=' . (string) $userAction;
    }
public function getPayPalCommunicationUrl ( $ token = null , $ userAction = 'continue' ) { return $ this -> getUrl ( ) . '&cmd=_express-checkout&token=' . ( string ) $ token . '&useraction=' . ( string ) $ userAction ; }
Returns redirect url.

@param string $token      token to append to redirect url.
@param string $userAction checkout button action - continue (standard checkout) or commit (express checkout)

@return string
Returns redirect url .