def METHOD_NAME(self):
    rw = models.Referencework.objects.create(
        institution=self.institution,
        referenceworktype=0)
    tc = self.roottaxon.taxoncitations.create(
        referencework=rw)
    with self.assertRaises(ProtectedError):
        self.roottaxon.delete()
    tc.delete()
    self.roottaxon.delete()