def __init__(self, samples_per_step=None):
        """
        Args:
            samples_per_step (int or None): total number of samples processed in each step
                (i.e., your total batch size in each step).
                If not provided, this callback will record "steps/sec" instead of "samples/sec".
        """
        if samples_per_step is not None:
            samples_per_step = int(samples_per_step)
        self._samples_per_step = samples_per_step
        self._timer = Timer()
        self._timer.pause()

        Args:
            samples_per_step (int or None): total number of samples processed in each step
                (i.e., your total batch size in each step).
                If not provided, this callback will record "steps/sec" instead of "samples/sec".
        
tensorpack/callbacks/prof.py