save-failure-html always gives TypeError

I always get this when trying to use the --save-failure-html argument:

$ aws-google-auth --role-arn arn:aws:iam::666666666:role/sso/sso-xxxxxxxx --duration 43200 --profile xx-xxxx --keyring --save-failure-html
Failed to import U2F libraries, U2F login unavailable. Other methods can still continue.
Open the Google App, and tap 'Yes' on the prompt to sign in ...
SAML lookup failed, storing failure page to 'saml.html' to assist with debugging.
Traceback (most recent call last):
  File "/Users/max.williams/Library/Python/3.6/lib/python/site-packages/aws_google_auth/google.py", line 284, in parse_saml
    saml_element = parsed.find('input', {'name': 'SAMLResponse'}).get('value')
AttributeError: 'NoneType' object has no attribute 'get'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/max.williams/Library/Python/3.6/bin/aws-google-auth", line 11, in <module>
    sys.exit(main())
  File "/Users/max.williams/Library/Python/3.6/lib/python/site-packages/aws_google_auth/__init__.py", line 232, in main
    cli(cli_args)
  File "/Users/max.williams/Library/Python/3.6/lib/python/site-packages/aws_google_auth/__init__.py", line 66, in cli
    process_auth(args, config)
  File "/Users/max.williams/Library/Python/3.6/lib/python/site-packages/aws_google_auth/__init__.py", line 192, in process_auth
    saml_xml = google_client.parse_saml()
  File "/Users/max.williams/Library/Python/3.6/lib/python/site-packages/aws_google_auth/google.py", line 290, in parse_saml
    out.write(self.session_state.text.encode('utf-8'))
TypeError: write() argument must be str, not bytes

[stevemac007]

Merging the fix to master - it looks like it was a defect with python3 and the save flag fix.

[max-rocket-internet]

This was fixed. Thanks @stevemac007!