code: def get_gce_driver(self):
          
          # Attempt to get GCE params from a configuration file, if one
          # exists.
          secrets_path = self.config.get('gce', 'libcloud_secrets')
          secrets_found = False
          try:
              import secrets
              args = list(getattr(secrets, 'GCE_PARAMS', []))
              kwargs = getattr(secrets, 'GCE_KEYWORD_PARAMS', {})
              secrets_found = True
          except:
              pass
  
          if not secrets_found and secrets_path:
              if not secrets_path.endswith('secrets.py'):
                  err = "Must specify libcloud secrets file as "
                  err += "/absolute/path/to/secrets.py"
                  sys.exit(err)
              sys.path.append(os.path.dirname(secrets_path))
              try:
                  import secrets
                  args = list(getattr(secrets, 'GCE_PARAMS', []))
                  kwargs = getattr(secrets, 'GCE_KEYWORD_PARAMS', {})
                  secrets_found = True
              except:
                  pass
          if not secrets_found:
              args = [
                  self.config.get('gce','gce_service_account_email_address'),
                  self.config.get('gce','gce_service_account_pem_file_path')
              ]
              kwargs = {'project': self.config.get('gce', 'gce_project_id')}
  
          # If the appropriate environment variables are set, they override
          # other configuration; process those into our args and kwargs.
          args[0] = os.environ.get('GCE_EMAIL', args[0])
          args[1] = os.environ.get('GCE_PEM_FILE_PATH', args[1])
          kwargs['project'] = os.environ.get('GCE_PROJECT', kwargs['project'])
  
          # Retrieve and return the GCE driver.
          gce = get_driver(Provider.GCE)(*args, **kwargs)
          gce.connection.user_agent_append(
              '%s/%s' % (USER_AGENT_PRODUCT, USER_AGENT_VERSION),
          )
          return gce
docs: Determine the GCE authorization settings and return a
          libcloud driver.