It is no defense to prosecution for perjury:

1. (1) That the oath was administered in an irregular manner.
2. (2) That there was some irregularity in the appointment or qualification of the person who administered the oath, if the taking of the oath was required or authorized by law.
3. (3) That the document was not sworn to if the document contains a recital that it was made under oath, the declarant was aware of the recital when he signed the document and the document contains the signed jurat of a public servant authorized to administer oaths.
4. (4) That the defendant mistakenly believed the false statement to be immaterial.
5. (5) That the statement was inadmissible under the law of evidence.

(Acts 1977, No. 607, p. 812, §4930.)