public function getCustomerTaxClasses()
    {
        /** @var \Magento\Tax\Model\ResourceModel\TaxClass\Collection $taxCollection */
        $classes       = [];
        $defaultTaxId  = $this->customerGroup->getNotLoggedInGroup()->getTaxClassId();
        $taxCollection = $this->taxClass->getCollection();
        $taxCollection->setClassTypeFilter(ClassModel::TAX_CLASS_TYPE_CUSTOMER);

        /** @var ClassModel $tax */
        foreach ($taxCollection as $tax) {
            $classes[] = [
                'id'         => $tax->getId(),
                'key'        => $tax->getClassName(),
                'is_default' => intval($defaultTaxId == $tax->getId()),
            ];
        }

        return $classes;
    }