cloudml job submission failed

Question

I am submitting deep learning jobs using cloudml_train() function from couldml R package, the following error occurs:

[errmsg]
ERROR: (gcloud.ai-platform.jobs.submit.training) Packaging of user Python code failed with message:

Traceback (most recent call last):
  File "/private/var/folders/mg/kk_npp915pj8hrr2qlkz8r0h2scn_3/T/RtmpXYP3NE/cloudml-deploy-train-459a20e76d9e/setup.py", line 8, in <module>
    import yaml
ModuleNotFoundError: No module named 'yaml'


Try manually building your Python code by running:
  $ python setup.py sdist
and providing the output via the `--packages` flag (for example, `--packages dist/package.tar.gz,dist/package2.whl)`

Any hints/solutions?