PageFormatSelector
Determines which pages a PageFormatInfo applies to. A selector can target a specific side (left/right pages), a range of 1-based page indices, or both (e.g. left pages within a given range).
A null selector on PageFormatInfo means global scope (all pages).
Parameters
side
the page side to target, or null for both sides
range
1-based inclusive range of page indices to target, or null for all pages