jan

The default behavior of [mashmallow-enum](https://github.com/justanr/marshmallow_enum) is [by_value=False](https://github.com/justanr/marshmallow_enum/blob/ed4af1846f93be800704325dda88b531c3fa127a/marshmallow_enum/__init__.py#L36). Its readme is not specifying this behavior. We have many Enums and in our case they should be serialized by value. This means...