def __enter__(self):
        self.cls._all_subclasses = self.cls._subclasses
        self.cls._subclasses = (self.cls,)
        return self.cls
Advance through the container generator until we get the packet
dataset/ETHPy150Open MongoEngine/mongoengine/mongoengine/context_managers.py/no_sub_classes.__enter__--crossover with--dataset/ETHPy150Open soft-matter/pims/pims/pyav_reader.py/PyAVVideoReader._seek_packet