static long recommendedTranspilationDateForStandardFunctions(Collection<S> sfNames) {
  long date = 0;
  for (S name : sfNames) {
    long d = recommendedTranspilationDateForStandardFunction(name);
    if (d == 0) ret 0; // unknown, retranspile
    date = max(date, d);
  }
  ret date;
}