code: func (l AncestorList) GetDistinctAncestorIDs() id.Slice {
  	m := id.Map{}
  	for _, ancestor := range l {
  		m[ancestor.ID] = struct{}{}
  	}
  	return m.ToSlice()
  }
docs: // GetDistinctAncestorIDs returns a list with distinct ancestor IDs.