(4) If a Bill is presented to the President for assent and it is not accompanied by a certificate which is required by any provision of this Constitution, the President must not assent to the Bill until the certificate is produced. (5) For the purposes of this section, a Bill is regarded as having been presented to the President for assent when Parliament transmits it to the President's office, and the date of its transmission must be recorded in the journal of the House from which it is transmitted. 137 Acts of Parliament and their commencement (1) All laws made by Parliament are called "Acts of Parliament" and the words of enactment are "enacted by the President and the Parliament of Zimbabwe" or words to that effect. (2) An Act of Parliament comes into operation at the beginning of the day on which it is published in the Gazette, or at the beginning of any other day that may be specified in the Act or some other enactment. 138 Enrolment of Acts (1) When an Act of Parliament has been assented to by the President, the Clerk of Parliament must transmit a fair copy of it, authenticated by the President's signature and the public seal of Zimbabwe, to be enrolled in the office of the Registrar of the High Court, and that copy is conclusive evidence of the provisions of the Act unless the Act is revised under an Act of Parliament referred to in subsection (2). (2) An Act of Parliament may provide for the statute law, or any part of it, to be published in revised form and may further provide that— (a) upon being published, the revision is the sole authentic version of the statutes contained in it; (b) a copy of the revision must be deposited in the office of the Registrar of the High Court; and (c) the copy that is deposited in the office of the Registrar of the High Court is conclusive evidence of the provisions of the statutes contained in it. (3) The validity of an Act of Parliament or a revision of the statute law does not depend on its enrolment or deposit under this section. 139 Amendment of Constitution (1) Subject to this section, an Act of Parliament may amend any or all of the provisions of this Constitution. (2) An Act of Parliament that amends this Constitution must do so in express terms. (3) A Constitutional Bill must not be introduced into the Senate or the National Assembly unless the text of the Bill has been published in the Gazette at least thirty days before it is introduced. (4) A Constitutional Bill is not regarded as having been passed by Parliament unless, at the final vote on the Bill in each House of Parliament, it receives the affirmative votes of at least two-thirds of the total membership of the House. (5) A Constitutional Bill that will amend any of the following provisions of this Constitution– (a) section one, which deals with the Republic; - 57 -