code: public <T> void put(String typeName, PrefabValueFactory<T> factory) {
          if (typeName != null) {
              cache.put(typeName, factory);
          }
      }
docs: Adds the given factory to the cache and associates it with the given
  type name.
  
  @param <T> Should match {@code typeName}.
  @param typeName The fully qualified name of the type.
  @param factory The factory to associate with {@code typeName}