nbrede

Currently datetimes are supported by specifying the type as `"datetime"` in a schema. This seems to be incompatible with the JSON schema and OpenAPI specifications, which state it should be...

When used to annotate a `PolymorphicQuerySet` from [django-polymorphic](https://github.com/django-polymorphic/django-polymorphic), this error is raised: ``` 'NoneType' object has no attribute 'query' in django/db/models/expressions.py in get_source_expressions at line 1051 def get_source_expressions(self): return [...