MyPy documentation mentions it's possible to mix required and non-required items in TypedDict:

class MovieBase(TypedDict):
    name: str
    year: int

class Movie(MovieBase, total=False):
    based_on: str

https://mypy.readthedocs.io/en/latest/more_types.html#mixing-required-and-non-required-items

Unfortunately, I couldn't find how to see which of Movie keys are required, in runtime. I can only get a list of all fields (__annotations__) and the fact Movie is non-total (__total__).

>>> from mypy_extensions import TypedDict
>>> class MovieBase(TypedDict):
...     name: str
...     year: int
... 
>>> class Movie(MovieBase, total=False):
...     based_on: str
... 
>>> Movie.__annotations__
{'based_on': <class 'str'>, 'name': <class 'str'>, 'year': <class 'int'>}
>>> Movie.__total__
False

Alternatively I could poke into original base classes to find out which keys are required, but I it doesn't work:

>>> Movie.__bases__
(<class 'dict'>,)

I'm trying to write a function that checks if data matches its TypedDict type, in runtime. I can't implement it without knowing which keys are required.