static L mapMethodLike dm_optPcallAll(S serviceName, S method, O... args) {
  ret dm_optPcallAll(dm_getServices(serviceName), method, args);
}

// also takes service names
static L mapMethodLike dm_optPcallAll(Cl moduleIDs, S method, O... args) {
  new L out;
  for unnull (O mod : moduleIDs)
    addIfNotNull(out, dm_pcallOpt(mod, method, args));
  ret out;
}

Began life as a copy of #1022563