The judgment debtor in the main action may file a claim of exemption setting forth any facts showing that the debt or the property with which it is sought to charge the garnishee is exempt from execution, or for any other reason is not liable for the judgment creditor’s claim, and if issue thereon be joined by the judgment creditor it shall be tried with the issues as to the garnishee’s liability, and if the property or debt, or any part thereof, is found to be thus exempt or not liable, judgment shall be rendered accordingly.