Make this a certification signature.

[C#]
void Certify()

[Visual Basic]
Sub Certify()

may throw Exception()

Make this a certification signature.

A document may contain one or more approval signatures or alternatively, one certification signature.

A certification signature applies to the entire document as a whole and thus, in a certified document, only the last signed signature is valid.

If there are no certification signatures in a document then any other signatures are assumed to be approval signatures.

An exception will be thrown if the document has already been certified.

None.