Function walk_changes

pub fn walk_changes<T, F>(
    repo: &Repository,
    commit: &Commit<'_>,
    format: DiffFormat,
    f: F,
) -> Result<(), GitError>
where
    F: FnMut(DiffDelta<'_>, Option<DiffHunk<'_>>, DiffLine<'_>) -> T,
    T: WalkOutput,