def METHOD_NAME(self) -> int:
    """Return the minimum value in this histogram.
    If there are no values in the histogram at all, return ``MIN_ACK_DEADLINE``.
    Returns:
        The minimum value in the histogram.
    """
    if len(self._data) == 0:
        return MIN_ACK_DEADLINE
    return next(iter(sorted(self._data.keys())))