Represents the "P" entry of the signature field lock dictionary object.

It is an optional entry defined as part of the PDF 1.7 Extension Level 3 specification.

It contains an integer representing a PDF numeric object.

It should have a minimum value of 1 and a maximum of 3.

The PDF specification states that this item assumes a value of 0 if no value has been provided.

For definitive details see:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 233, page 447.

Adobe Supplement to the ISO 32000, BaseVersion: 1.7, ExtensionLevel: 3; Table: 8.82, page 43.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 236, page 541.