Function placed 

fn placed(table: Table, at: Option<isize>) -> Table

A table read from an entry’s text, placed in a file: written where it stands, its own tables under it. toml_edit writes a file’s tables in the order of the positions they were read at; those read from the entry’s text would put them out of place (a project’s routes under the project after it). So its tables keep none, and it takes at, the position of the one it replaces.