prevent quadratic time removal of duplicates if filter list is empty (likely to have too many results)
prevent quadratic time removal of duplicates if filter list is empty (likely to have too many results)

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle