Copyright Government of Botswana 
discharging the functions of his or her office and the infirmity is of such a nature that the President is unable to authorize another person under this section to perform the functions of his or her office; or  (b) the Vice-President is by reason of physical or mental infirmity unable to discharge the functions of his or her office, shall, in respect of any period for which it is in force, be conclusive and shall not be questioned in any court:  Provided that any such certificate as is referred to in paragraph (a) of this subsection shall cease to have effect if the President notifies any person under subsection (4) of this section that he or she is about to resume the functions of the office of President. 37. Oath of President   A person assuming the office of President shall, before entering upon the duties of that office, take and subscribe such oaths as may be prescribed by Parliament. 38. Returning officer at elections of President   (1) The Chief Justice shall be the returning officer for the purposes of elections to the office of President.  (2) Any question which may arise as to whether-  (a) any provision of this Constitution or any law relating to the election of a President under section 32 or 35 of this Constitution has been complied with; or  (b) any person has been validly elected as President under those sections, shall be referred to and determined by the returning officer whose decision shall not be questioned in any court. 39. Vice President   (1) There shall be a Vice-President who shall be appointed by the President from among the Elected Members of the National Assembly who are citizens of Botswana by birth or descent, which appointment shall be endorsed by the said Elected Members.  (2) The Vice-President shall continue in office until a person elected at the next election of President under section 32 or 35 of this Constitution assumes office:  Provided that the office of Vice-President shall become vacant-  (i) if the appointment of the holder of the office is revoked by the President; or  (ii) if the holder of the office ceases to be a Member of the National Assembly for any other reason than a dissolution of Parliament.  (3) The Vice-President shall not enter upon the duties of his or her office unless he or she has taken and subscribed the oath of allegiance and such oath for the due execution of his or her office as may be prescribed by Parliament.  (4) If the Vice-President is absent from Botswana or is incapable by reason of illness or any other cause of discharging the functions of his or her office, the President may appoint a person, from among the Members of the Assembly, to perform the functions of the office of Vice-President and any person so appointed may discharge those functions accordingly:  Provided that a person appointed under this subsection shall cease to perform the functions of the office of Vice-President-  (i) if his or her appointment is revoked by the President;  (ii) if he or she ceases to be a Member of the Assembly otherwise than by reason of a dissolution of Parliament;  (iii) upon the assumption by any person of the office of President; or  (iv) upon the President giving him or her notice that the Vice-President is about to resume his or her functions.  (5) Where the Vice-President is performing the functions of the office of President in accordance with section 35 or 36 of this Constitution he or she may appoint a person,