def unregister(model_or_iterable, fail_silently=False):
    from django.db import models
    from .compat import get_model

    if issubclass(model_or_iterable, models.Model):
        model_or_iterable = [model_or_iterable]
    for model in model_or_iterable:
        if isinstance(model, string_types):
            model = get_model(*model.split('.', 1))
        try:
            del REGISTRY[model]
        except KeyError:
            if fail_silently:
                continue
            raise ValueError(
                u'The model %s.%s is not registered.' % (
                    model._meta.app_label,
                    model._meta.object_name,
                ))
Returns the proper null SRID depending on the GEOS version.
dataset/ETHPy150Open gregmuellegger/django-autofixture/autofixture/__init__.py/unregister--crossover with--dataset/ETHPy150Open cloudera/hue/desktop/core/ext-py/Django-1.6.10/django/contrib/gis/geos/tests/test_geos.py/GEOSTest.null_srid