What happens when capture is defined as def capture(**metadata) and called as capture(**{…

What happens when capture is defined as def capture(**metadata) and called as capture(**{"content-type": "json"})?

1. metadata becomes {'content-type': 'json'} because the mapping key is a string.
2. It raises SyntaxError because the key contains a hyphen.
3. It raises TypeError because every keyword key must be a valid identifier.
4. metadata becomes {'content': 'json'} after normalization.