It is not a defense to a prosecution under this part:
(1) That the defendant was not competent, for reasons other than lack of penal responsibility, to make the false statement alleged;
(2) That the statement was inadmissible under the law of evidence;
(3) That the oath was administered or taken in an irregular manner; or
(4) That the person administering the oath lacked authority to do so, if the taking of the oath was required or authorized by law.