Therefore, it is a good idea to distinguish between sharing with learners and sharing with collaborators in each case. For example, if you limit visibility of a worksheet to students and reset the sharing level to Private, collaborators will still be able to access and work on the worksheet, but students will not. In this sense, the sharing level applies only to students, and colleagues added to the collaborators field will be able to access the worksheet with the permissions you specify, regardless of the sharing level.