What about defining an inlined typed dictionay extending another typed dictionary?:
InlinedBase = TypedDict[{'a': int}] Inlined = TypedDict[InlinedBase, {'b': int}]
How about something like this:
Inlined = TypedDict[{'b': int} : InlinedBase]
Languages like Kotlin and C# use a similar syntax for inheritance.
And even though I have barely any experience with such languages, this unconventional slice operator usage looks very natural to me 
.
Thoughts?