Typing for classes inheriting HyperlinkedIdentityField

[Alexerson]

It seems that the following changes introduced a bug:
133e572

It’s possible to not pass any view_name to a HyperlinkedRelatedField if you create a subclass that will define the view_name directly.

For instance:

class BookField(serializers.HyperlinkedRelatedField):
    view_name = 'book-detail'

    def get_queryset(self):
        return Book.objects.all()

is valid.
Right now mypy wrongfully complains with:

error: Missing positional argument "view_name" in call to "BookField"  [call-arg]