public function isValid($discount, $request)
    {
        $code = $this->validate($discount, $request);
        if ($code == Discount_Engine::VALIDATION_CODE_VALID)
            return true;
        return false;
    }
public function isValid($discount, $request)
    {
        $code = $this->validate($discount, $request);
        if ($code == Discount_Engine::VALIDATION_CODE_VALID)
            return true;
        return false;
    }
public function isValid ( $ discount , $ request ) { $ code = $ this -> validate ( $ discount , $ request ) ; if ( $ code == Discount_Engine :: VALIDATION_CODE_VALID ) return true ; return false ; }
Check if give discount is valid or not.

@param Discount_Discount $discount
@param Pluf_HTTP_Request $request
Check if give discount is valid or not .