This ordinance shall become operative on April 1, 1956, and prior thereto this City shall contract with the State Board of Equalization to perform all functions incident to the administration and operation of this sales and use tax ordinance, provided, that if this City shall not have contracted with the said State Board of Equalization, as above set forth, prior to April 1, 1956, this ordinance shall not be operative until the first day of the first calendar quarter following the execution of such a contract by the City and by the State Board of Equalization; provided, further, that this ordinance shall not become operative prior to the operative date of the Uniform Local Sales and Use Tax Ordinance of the County of Los Angeles.