/**
* Get the base fee tax based on the shipping address and tax rate.
*
* @param Mage_Customer_Model_Address_Abstract $address
* @param float $taxRate
* @param float|null $fee
* @param boolean $isInclTax
*
* @return float
*/
protected function _getBaseBuckarooFeeTax($address, $taxRate, $fee = null, $isInclTax = false)
{
if (is_null($fee)) {
$fee = (double) $address->getBaseBuckarooFee();
}
$taxCalculation = $this->getTaxCalculation();
$baseFeeTax = $taxCalculation->calcTaxAmount($fee, $taxRate, $isInclTax, false);
return $baseFeeTax;
}