2.4.0 Python mobile gaming leader_board example is not working

The leader_board example does not work on DirectRunner. No result are generated.

Run Injector to simulate data:

  mvn compile exec:java \
  -Dexec.mainClass=org.apache.beam.examples.complete.game.injector.Injector \
  Dexec.args="<gcloud_project> <pubsub_topic> none" 

Setup virtualenv and install python sdk from https://dist.apache.org/repos/dist/dev/beam/2.4.0/

  virtualenv temp_virtualenv
  . temp_virtualenv/bin/activate && pip install apache-beam-2.4.0-python.zip

Run leader_board:

  python -m apache_beam.examples.complete.game.leader_board \
  --project=<gcloud_project>\
  --topic projects/<gcloud_project>/topics/<pubsub_topic>\
  --dataset=<bq_dataset> \
  --runner=DirectRunner \
  --table=<bq_table_name>