def __getitem__(self, key):
        return self.meta_ext.get_class_dict(('global', 'const'))[key]
is_creatable should not be inherited in the normal manner, and should
dataset/ETHPy150Open moloney/dcmstack/src/dcmstack/dcmmeta.py/NiftiWrapper.__getitem__--crossover with--dataset/ETHPy150Open torchbox/wagtail/wagtail/wagtailcore/tests/test_page_model.py/TestIsCreatable.test_is_creatable_not_inherited