def register(self, model):
        from django.db import models
        if self in model:
            raise ImproperlyConfigured(
                "You cannot register the same model ('{0}') twice."
                .format(model)
            )
        if not issubclass(model, models.Model):
            raise ImproperlyConfigured(("{0} is not a subclass of django.db.models.Model, "
                                        "so it cannot be registered").format(model))
        if model._meta.abstract:
            raise ImproperlyConfigured("You cannot register the abstract class {0}".format(model))
        self.add(model)

        # allow use as a decorator
        return model
dataset/ETHPy150Open fusionbox/django-widgy/widgy/__init__.py/BaseRegistry.register/swapped operands of `in`