Function dope_card_page_count 

pub fn dope_card_page_count(row_count: usize, font_scale: f32) -> usize

Pages generate_dope_card_pdf emits for row_count rows at font_scale.

0 rows is 0 pages — that call errors rather than producing an empty document, so a zero here is a caller’s row set to reject, not a document to describe.