svoid dm_changeModuleLibID(O mod, S newLibID) {
  O stem = dm_getStem(mod);
  if (stem == null) ret;
  LS l = splitAtSlash(newLibID);
  if (l(l) != 2) fail("Not a valid lib ID: " + quote(newLibID));
  S moduleID = assertSnippetID(first(l));
  S _className = assertIdentifier(second(l));
  print("Morphing module " + dm_moduleIDAndName(stem) + " into type " + moduleID + "/" + _className); 
  call(stem, '_setFields, +moduleID, +_className);
  dm_reloadModule(stem);
}