def changelist_view(self, request, extra_context=None):
        with self._create_revision(request):
            context = {
                "has_change_permission": self.has_change_permission(request),
            }
            context.update(extra_context or {})
            return super(VersionAdmin, self).changelist_view(request, context)
Remove null values in a nested set of arguments, eliminates unpassed values in S3.
dataset/ETHPy150Open etianen/django-reversion/src/reversion/admin.py/VersionAdmin.changelist_view--crossover with--dataset/ETHPy150Open chapmanb/bcbio-nextgen-vm/bcbiovm/ship/pack.py/_remove_empty