flags arguments do not propagate

[leonjessen]

If I run the following command

> my_job = cloudml_train(file = "R/06_train_model.R", master_type = "standard_p100", flags = c("--runtime-version 2.1", "--python-version 3.7"), dry_run = FALSE)

I get the following error, where the stated flags parameter is not propagated:

Submitting training job to CloudML...
Error: ERROR: gcloud invocation failed [exit status 1]

[command]
/Users/USER/google-cloud-sdk/bin/gcloud --account USER@DOMAIN --project my-first-cloudml-project ai-platform jobs submit training cloudml_2020_08_24_075738788 --job-dir=gs://my-first-cloudml-project/r-cloudml/staging --package-path=cloudml-model --module-name=cloudml-model.cloudml.deploy --runtime-version=1.9 --region=us-central1 --config=cloudml-model/cloudml.yml -- Rscript

[output]


[errmsg]
ERROR: (gcloud.ai-platform.jobs.submit.training) INVALID_ARGUMENT: Field: runtime_version Error: The specified runtime version '1.9' with the Python version '' is not supported or is deprecated.  Please specify a different runtime version. See https://cloud.google.com/ml-engine/docs/runtime-version-list for a list of supported versions
- '@type': type.googleapis.com/google.rpc.BadRequest
  fieldViolations:
  - description: The specified runtime version '1.9' with the Python version '' is
      not supported or is deprecated.  

Changing the flags parameter to flags = "--runtime-version 2.1 --python-version 3.7" yields the same error