How CSV imports affect existing collections

I'm currently working on creating a csv file to batch make collections. How does this affect collections that already exist?

When creating new collections via a CSV file, the system will automatically add them. If you include sub-collections under an existing parent (using path logic), only the missing collections will be created and added to the collection tree.

Example:
- You have a collection called 2026, and inside it a sub-collection named Test. To add a new sub-collection under it, use the following CSV path format:
  - 2026/Test/Day1
- If you want to add multiple sub-collections, add each one as a separate row in the CSV:
  - 2026/Test/Day2
    2026/Test/Day3
    2026/Test/Day4
- To add sub-collections under the Day collections, include an additional level in the path:
  - 2026/Vancouver Series/Day1/photo
    2026/Vancouver Series/Day1/video
    2026/Vancouver Series/Day2/photo
    2026/Vancouver Series/Day2/video