7. Proceedings and evidence not invalidated by omission of oath or irregularity.- No omission to take any oath or make any affirmation, no substitution of any one for any other of them, and no irregularity whatever in the administration of any oath or affirmation or in the form in which it is administered, shall invalidate any proceeding or render inadmissible any evidence whatever, in or in respect of which such omission, substitution or irregularity took place, or shall affect the obligation of a witness to state the truth. | 