code: func fetchPreviousVersions(ref string, since time.Time, filter *filepathfilter.Filter) bool {
  	var pointers []*lfs.WrappedPointer
  
  	tempgitscanner := lfs.NewGitScanner(func(p *lfs.WrappedPointer, err error) {
  		if err != nil {
  			Panic(err, "Could not scan for Git LFS previous versions")
  			return
  		}
  
  		pointers = append(pointers, p)
  	})
  
  	tempgitscanner.Filter = filter
  
  	if err := tempgitscanner.ScanPreviousVersions(ref, since, nil); err != nil {
  		ExitWithError(err)
  	}
  
  	tempgitscanner.Close()
  	return fetchAndReportToChan(pointers, filter, nil)
  }
docs: // Fetch all previous versions of objects from since to ref (not including final state at ref)
  // So this will fetch all the '-' sides of the diff from since to ref