Custom view class incorrectly rejects View subclasses

[kyleect]

It should be view_cls not view_cls.__class__

    if view_cls is not None and not issubclass(view_cls.__class__, View):
        raise ValueError(f"cls must be a subclass of View")

    if view_cls is not None and not issubclass(view_cls.__class__, View):
        raise ValueError(f"cls must be a subclass of View")