'Args:
monitor_stat(str): the name of the statistics.
reverse (bool): if True, will save the maximum.
filename (str): the name for the saved model.
Defaults to ``min-{monitor_stat}.tfmodel``.
Example:
Save the model with minimum validation error to
"min-val-error.tfmodel":
.. code-block:: python
MinSaver(\'val-error\')
Note:
It assumes that :class:`ModelSaver` is used with
``checkpoint_dir=logger.LOG_DIR`` (the default). And it will save
the model to that directory as well.'

def __init__(self, monitor_stat, reverse=False, filename=None):

    self.monitor_stat = monitor_stat
    self.reverse = reverse
    self.filename = filename
    self.min = None
