Powers of Mayor and Deputy Mayor whose term of office stands extended and validation of certain acts

All the Mayors and Deputy Mayors of the Municipal Corporations, whose term of office is deemed to have been extended or is extended, as the case may be, under section 3, shall, throughout such extended period, be deemed to have been and be competent to exercise all the powers, perform all the duties and discharge all the functions as such Mayor and Deputy Mayor ; and no act done by any of them during the said period shall be invalid, or shall be called in question in any court, merely on the ground that during the extended period such Mayor and Deputy Mayor could not exercise all or any of the powers or perform all or any of the duties or discharge all or any of the functions of the Mayor and Deputy Mayor under the relevant Acts.