Many people have requested support for a way to type **kwargs with a TypedDict. There have been proposals to support this using the Unpack type introduced in the recently-accepted PEP 646.

It would be good to prototype this to uncover any potential issues.

• How to handle required fields that are not supplied by the caller?
• How to handle function assignment when the source type contains one of these unpacked TypedDicts?
• Is it necessary/desirable to support unions of TypedDicts? This adds significant complexity.
• Should it support * unpack operator introduced in PEP 646?
• How to handle references to kwargs within the function implementation? Is it the same as any other TypedDict reference?
• How do we deal with the case where a keyword parameter has a name that overlaps with an entry in the TypedDict?
• Should it be an error if an unpacked mapping (with unknown keys) is passed to the function?