There is, but it causes issues when passing it to the method rather than using self.args.yaml_file.

jeff@periodic-a003:~$ kcollectd2-python update-ec2-tags.py --test
Traceback (most recent call last):
  File "update-ec2-tags.py", line 111, in <module>
    main()
  File "update-ec2-tags.py", line 107, in main
    app.update_tags(app.args.yaml_file)
  File "update-ec2-tags.py", line 75, in update_tags
    with open(yaml_file, 'r') as yamlfile:
TypeError: coercing to Unicode: need string or buffer, file found