Each Borrower will duly pay and discharge, or cause to be paid and discharged, before the same shall become overdue, all Taxes, assessments and other governmental charges imposed upon them and their real properties, sales and activities, or any part thereof, or upon the income or profits therefrom, as well as all claims for labor, materials, or supplies that if unpaid might by law become a lien or charge upon any of its properties; provided , that any such Tax, assessment, charge, levy or claim need not be paid if the validity or amount thereof shall be the subject of a Permitted Contest; and provided further that such Borrower shall pay all such Taxes, assessments, charges, levies or claims forthwith upon the commencement of proceedings to foreclose any Lien that may have attached as security therefor. Each Borrower will accurately prepare and timely file all tax returns required by law to be filed by it.