code: protected String printConcept(int id) {
          Object oid = factory.lookupConceptId(id);
          if(factory.isVirtualConcept(id)) {
              if(oid instanceof AbstractConcept) {
                  return printAbstractConcept((AbstractConcept) oid);
              } else {
                  return oid.toString();
              }
          } else {
              return (String) oid;
          }
      }
docs: Prints a concept given its internal id. Useful for debugging.
  
  @param id
  @return