Launch job on ML Engine.

def launch_job(job_spec):
  """Launch job on ML Engine."""
  project_id = "projects/{}".format(
      text_encoder.native_to_unicode(default_project()))
  credentials = GoogleCredentials.get_application_default()
  cloudml = discovery.build("ml", "v1", credentials=credentials,
                            cache_discovery=False)
  request = cloudml.projects().jobs().create(body=job_spec, parent=project_id)
  request.execute()