def __init__(self, devices=(0,)):
        """
        Args:
            devices([int] or [str]): list of GPU devices to track memory on.
        """
        assert isinstance(devices, (list, tuple)), devices
        devices = ['/gpu:{}'.format(x) if isinstance(x, int) else x for x in devices]
        self._devices = devices
        self._disabled = False

        Args:
            devices([int] or [str]): list of GPU devices to track memory on.
        
tensorpack/callbacks/prof.py