Fix typo in serialization for Container::None

[zackangelo]

Proposed changes

• Fix serialization bug that causes an API error for Container::None

Types of changes

• [x] Bugfix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] Documentation update or tests (if none of the other choices apply)

Checklist

• [x] I have read the CONTRIBUTING.md doc
• [ ] I have added tests and/or examples that prove my fix is effective or that my feature works
• [ ] I have added necessary documentation (if appropriate)