Each Seller Party and each Guarantor shall timely file all tax returns that are required to be filed by them and shall timely pay and discharge all taxes, assessments and governmental charges or levies imposed on it or on its income or profits or on any of its property prior to the date on which penalties attach thereto, except for any such tax, assessment, charge or levy the payment of which is being contested in good faith and by proper proceedings and against which adequate reserves are being maintained.