# Cleanup pairs [Obj,Obj]

### Description
Cleanup pairs in `SOURCE`, by e.g. removing self-pairs, symmetrical pairs, etc.
When removing symmetrical pairs, it is unknown which of the two variants (a,b) or (b,a) will be removed.

### Input
- `SOURCE [OBJ,OBJ]`: a list of object pairs

### Output
- `RESULT [OBJ,OBJ]`: a list of object pairs