bim.reassign_class wasn't considering that root.reassign_class will also reassign class for occurrences of the same type and was reaccessing invalid elements
The issue was related to the sheet names - Excel prohibits some symbols in the names and it doesn't allow sheet name to be longer than 31 symbols. If sheet names doesn't match this criteria then Excel says file appears to be corrupted - when file open data itself is not really corrupted besides the spreadsheet names that failed the criteria.
* initial ui
* changed the group name
* groups counter in ui
* added operators for selection and breaking link in the ui
* small removal
* changed IFC operators to _execute
* added simples linked aggregate test
* small fix in remove_old_connections function
* added test for refresh linked aggregate
* refresh linked aggregates now preserves the objects original name
* small fix in recreate_connections function
* tests for Refresh Linked Aggregate
* test for Refresh Linked Aggregate after copying an object
* small deletion
* added custom incremental naming
* small fix in tests
* small fix on the number for renaming
as probably in the most cases user would want 1 style per 1 representation item
After this it's finally possible in BBIM to assign styles to representation items through the materials: https://imgur.com/a/cgiJ1KV