As used in this chapter:
(a) “Act of Congress” means the act of Congress approved June 18, 1934, titled “An act to provide for the establishment, operation, and maintenance of foreign-trade zones in ports of entry of the United States, to expedite and encourage foreign commerce, and for other purposes” (48 U. S. Stats. at L. Ch. 590.).
(b) “Public corporation” means the state, any political subdivision thereof, any incorporated municipality therein, any public agency of the state, of any political subdivision thereof, or of any municipality therein, or any corporate municipal instrumentality of this state, or of this state and one or more other states.