75. Enhanced punishment for certain offenders under Chapter XII or Chapter XVII after previous conviction : Whoever, having been convicted" (a) by a Court in Pakistan of an offence punishable under Chapter XII or Chapter XVII of this Code with imprisonment of either description for a term of three years or upwards, or (b) [Omitted by thQ Federal Laws (Revision and Declaration), Ordinance, XXV// of 1981]. shall be guilty of any offence punishable under either of those Chapters with the imprisonment for the like term, shall be subject for every such subsequent offence to imprisonment for life, or to imprisonment of either description for a term which may extend to ten years. CHAPTER IV GENERAL EXCEPTIONS 76. Act done by a person bound, or by mistake of fact believing himself bound, by law: Nothing is an offence which Is done by a person who is, or who by reason of a mistake of fact and not reason of a mistake of law in good faith believes himself to be, bound by law to do it. Illustrations (a) A, a soldier, fires on a mob by the order of his superior officer, in conformity, with the commands of the law. A has committed no offence. (b) A an officer of a Court of Justice, being ordered by that Court to arrest Y and after due enquiry, believing Z to be Y arrests Z. A has committed no offence. 77. Act of Judge when acting judicially: Nothing is an offence which is done by a Judge when acting judicially in the exercise of any power which is, or which in good faith he believes to be,' given to him by law. 78. Act done pursuant to the judgment or order of Court: Nothing which is done in pursuance of, or which is warranted by the judgment or order of, a Court of Justice, if done whilst such judgment or order remains in force, is an offence, notwithstanding the Court may have had no jurisdiction to pass such judgment or order, provided the person doing the act in good faith believes that the Court had such jurisdiction. 79. Act done by a person justified, or by mistake of fact believing himself justified, by law: Nothing is an offence which is done by any person who is justified by law, or who by reason of a mistake of fact and not by reason of a mistake of law in good faith, believes himself to be justified by law, in doing it. Illustration