public function withCashBack($cashBackAmount)
    {
        $this->cashBackAmount = $cashBackAmount;
        $this->transactionModifier = TransactionModifier::CASH_BACK;
        return $this;
    }
public function withCashBack($cashBackAmount)
    {
        $this->cashBackAmount = $cashBackAmount;
        $this->transactionModifier = TransactionModifier::CASH_BACK;
        return $this;
    }
public function withCashBack ( $ cashBackAmount ) { $ this -> cashBackAmount = $ cashBackAmount ; $ this -> transactionModifier = TransactionModifier :: CASH_BACK ; return $ this ; }
Set the request cashback amount

@param string|float $cashbackAmount Request cashback amount

@return AuthorizationBuilder
Set the request cashback amount