static Concepts newConceptsWithClassFinder(S progID) {
  Concepts cc = new(progID);
  cc.classFinder = _defaultClassFinder();
  ret cc;
}

static Concepts newConceptsWithClassFinder(File conceptsFile) {
  Concepts cc = new(assertNotNull(conceptsFile));
  cc.classFinder = _defaultClassFinder();
  ret cc;
}

static Concepts newConceptsWithClassFinder(File conceptsFile, IF1<S, Class> classFinder) {
  Concepts cc = new(assertNotNull(conceptsFile));
  cc.classFinder = classFinder;
  ret cc;
}

Began life as a copy of #1020879