- Remove unnecessary parameter from `errors_report` function.
- Pass `Collection` by mutable reference to `export` function.
- Fix `.collection` file content in export test.
- Update test cases to reflect changes.
- Correct path in test data.
- Use mutable reference for `col` in `Tree.export`.
Co-authored-by: mahmmoud.hassanein <mahmmoud.hassanein@gmail.com>