code: @Override
      public Set<UnknownTypeValue> find() {
          if (!arePossibleInitialValuesAlreadyFound) {
              findPossibleInitialValues();
              arePossibleInitialValuesAlreadyFound = true;
          }
          return Collections.unmodifiableSet(possibleInitialValues);
      }
docs: Gets all possible values the given variable may have after initialisation
  of its class. {@link #run()} has to be invoked beforehand!
  
  @return all possible values the given variable may have after
  initialisation of its class. This is never {@code null} .
  @throws IllegalStateException
  if {@code run} was not invoked before this method.