code: private TypeContainer getProperty(String propName) {
          TypeContainer container = cache.get(propName);
          if (container == null) {
              container = new TypeContainer(propName, config, version);
              TypeContainer existing = cache.putIfAbsent(propName, container);
              if (existing != null) {
                  return existing;
              }
          }
  
          return container;
      }
docs: Gets the cached property container or make a new one, cache it and return it
  
  @param propName
  @return the property's container