code: private static Map<TypeVariable<?>, Type> mergeMaps(TypeDiscoverer<?> parent, Map<TypeVariable<?>, Type> map) {
  
          Map<TypeVariable<?>, Type> typeVariableMap = new HashMap<TypeVariable<?>, Type>();
          typeVariableMap.putAll(map);
          typeVariableMap.putAll(parent.getTypeVariableMap());
  
          return typeVariableMap;
      }
docs: Merges the type variable maps of the given parent with the new map.
  
  @param parent must not be {@literal null}.
  @param map must not be {@literal null}.
  @return