code: public EntityManager createLocalEntityManager(String serviceURL, String projectId,
        String namespace) {
      ConnectionParameters parameters = new ConnectionParameters();
      parameters.setServiceURL(serviceURL);
      parameters.setProjectId(projectId);
      parameters.setNamespace(namespace);
      return createEntityManager(parameters);
    }
docs: Creates and returns an {@link EntityManager} that allows working with the local Datastore
  (a.k.a Datastore Emulator). Specified project ID will be used.
  
  @param serviceURL
  Service URL for the Datastore Emulator. (e.g. http://localhost:9999)
  @param projectId
  the project ID. The specified project need not exist in Google Cloud. If
  <code>null</code>, default project ID is used, if it can be determined.
  @param namespace
  the namespace (for multi-tenant datastore) to use.
  @return an {@link EntityManager} that allows working with the local Datastore (a.k.a Datastore
  Emulator). If <code>null</code>, default namespace is used.