" Section 4 of the Fourth Amendment Act sought to validate the actions taken earlier by providing as under: "4(1) Notwithstanding anything in the provisions of the principal Act or any order of the Government made under the rule 12 in Schedule IX to the Principal Act, any,action taken till the commencement of this Act by any municipal council to continue to levy and collect the property tax in accordance with the method or manner or assessment or levy as provided in the Andhra Pradesh (Andhra Area) District Municipalities Act, 1920 or the Andhra Pradesh (Telangana Area) District Municipalities Act, 1956, as the case may be, shall not be deemed to be invalid or ever to have been invalid by reason only of the fact that such action was taken by the said municipal council during the period when the power in this behalf had not been validly entrusted to it in accordance with the provisions of the principal Act or the rules made thereunder and accordingly: (a) The levy and collection of property tax made in pursu ance of such action shall for all purposes be deemed to be, and to have always been, made in accordance with law; and (b) no suit or other proceeding shall be instituted or continued in any court against the municipal council con cerned or any person or authority whatsoever on its behalf on the ground only that any such action or levy and collec tion was not taken or made in accordance with law.