_field_types of typing.NamedTuple has been deprecated and will be removed in Python 3.9

[tirkarthi]

jsons/jsons/deserializers/default_tuple.py

Line 56 in e335fd5

hint = getattr(cls, '_field_types', {}).get(field_name)

https://docs.python.org/3/whatsnew/3.8.html#deprecated

The typing.NamedTuple class has deprecated the _field_types attribute in favor of the 
__annotations__ attribute which has the same information. 
(Contributed by Raymond Hettinger in bpo-36320.)

[ramonhagenaars]

Hi @tirkarthi. I see you also created a pull request for this: thank you! I'll address it soon.