core/checkpoint/manager.py

class ShadowCheckpointManager:
    def __init__(self, **kwargs):
        pass
    def list_checkpoints(self, *a):
        return []
    def diff_checkpoint(self, *a):
        return {}
    def restore_checkpoint(self, *a, **kw):
        return {}
    def get_files_at_checkpoint(self, *a):
        return []