Hi great project thanks very much!

I have the following use case and I am wondering if it can perhaps already be achieved? I have taken a look at the source and not sure that it can be! Maybe what I want to do is crazy!?

I have some function;

def foo(date: datetime.date) -> DataFrame:
    df = call_to_an_external_api(date)
    return df

The particular api is supposed to respond with data for only a single day specified by date - however sometimes data from days either side leak in - I would like to check that a column of df is unique and that all its values are date. However I don't know date until the function is called.

Could it be possible for a check decorator to pass in the decorated functions args in some way so this could be possible?