(3)If any question arises whether any matter is or is not a matter as respects which the Governor-General is by or under this Act required to act in his discretion or to exercise his individual judgment, the decision of the Governor-General in his discretion shall be final, and the validity of anything done by the Governor-General shall not be called in question on the ground that he ought or ought not to have acted in his discretion, or ought or ought not to have exercised his individual judgment.
