Compares two checkpoints based on the attribute attr_mean param.
        Greater than is used by default. If  command-line parameter
        checkpoint_score_attr starts with "min-" less than is used.

        Arguments:
            attr_mean: mean of attribute value for the current checkpoint

        Returns:
            True: when attr_mean is greater than previous checkpoint attr_mean
                  and greater than function is selected
                  when attr_mean is less than previous checkpoint attr_mean and
                  less than function is selected
            False: when attr_mean is not in alignment with selected cmp fn

def compare_checkpoints(self, attr_mean):
        """Compares two checkpoints based on the attribute attr_mean param.
        Greater than is used by default. If  command-line parameter
        checkpoint_score_attr starts with "min-" less than is used.

        Arguments:
            attr_mean: mean of attribute value for the current checkpoint

        Returns:
            True: when attr_mean is greater than previous checkpoint attr_mean
                  and greater than function is selected
                  when attr_mean is less than previous checkpoint attr_mean and
                  less than function is selected
            False: when attr_mean is not in alignment with selected cmp fn
        """
        if self._cmp_greater and attr_mean > self.best_checkpoint_attr_value:
            return True
        elif (not self._cmp_greater
              and attr_mean < self.best_checkpoint_attr_value):
            return True
        return False