pub fn with_part(
names: Names,
story: &str,
file: &str,
source: &str,
) -> Result<Names, Vec<ContentError>>Expand description
names (the table of file story) with the names of source added
(a second file, the test files’ names, say). source is checked like a names
file of its own, attributing errors to file; an id or a name that
names has too is an error.