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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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()