svoid tok_typeAA(L<S> tok, Set<S> pairClasses) {
  int n = l(tok)-6;
  bool change = false;
  for (int i = 1; i < l(tok); i += 2) {
    if (!(eq(get(tok, i+2), "<") && contains(pairClasses, tok.get(i)))) continue;
    if (tok_isSingleTypeArg(tok, i+2)) {
      int j = findEndOfTypeArgs(tok, i+2)-1;
      S type = joinSubList(tok, i+4, j);
      replaceTokens_reTok(tok, i+4, j, type + ", " + type);
      change = true;
    }
  }
}