'हेडन के मामले में नियम' (Rule in Heydon's case) को व्याख्या के निम्नलिखित में से किस नियम के रूप में भी जाना जाता है?

In the validation section (Sec. 6) of an Act, all acts done or omitted to be done are deemed to be so under this Act, as if such provisions were in force at the time such things:

'Rule in Heydon's case' is also known as:

Which of the following refers to the aids of construction that are located outside the text of the statute itself?