Seller shall timely file all income, franchise and other tax returns required to be filed by it and shall timely pay and discharge all taxes, levies, assessments, liens and other charges imposed on it, on its income or profits, on any of its property or on the Collateral prior to the date on which penalties attach thereto, except for any such tax, levy, assessment, liens or other charge which is being contested in good faith and by proper proceedings and against which adequate reserves are being maintained in accordance with GAAP.