How to use the skorch.exceptions.SkorchException function in skorch

"""Contains skorch-specific exceptions and warnings."""


class SkorchException(BaseException):
    """Base skorch exception."""


class NotInitializedError(SkorchException):
    """Module is not initialized, please call the ``.initialize``
    method or train the model by calling ``.fit(...)``.

    """


class SkorchWarning(UserWarning):
    """Base skorch warning."""


class DeviceWarning(SkorchWarning):
    """A problem with a device (e.g. CUDA) was detected."""

def on_epoch_end(self, net, **kwargs):
        if self.monitor is None:
            do_checkpoint = True
        elif callable(self.monitor):
            do_checkpoint = self.monitor(net)
        else:
            try:
                do_checkpoint = net.history[-1, self.monitor]
            except KeyError as e:
                raise SkorchException(
                    "Monitor value '{}' cannot be found in history. "
                    "Make sure you have validation data if you use "
                    "validation scores for checkpointing.".format(e.args[0]))

        if do_checkpoint:
            target = self.target
            if isinstance(self.target, str):
                target = self.target.format(
                    net=net,
                    last_epoch=net.history[-1],
                    last_batch=net.history[-1, 'batches', -1],
                )
            if net.verbose > 0:
                print("Checkpoint! Saving model to {}.".format(target))
            net.save_params(target)

conjunction with dirname.

        """
        if not self.dirname:
            return

        def _is_truthy_and_not_str(f):
            return f and not isinstance(f, str)

        if (
                _is_truthy_and_not_str(self.f_optimizer) or
                _is_truthy_and_not_str(self.f_params) or
                _is_truthy_and_not_str(self.f_history) or
                _is_truthy_and_not_str(self.f_pickle)
        ):
            raise SkorchException(
                'dirname can only be used when f_* are strings')

def on_epoch_end(self, net, **kwargs):
        if "{}_best".format(self.monitor) in net.history[-1]:
            warnings.warn(
                "Checkpoint monitor parameter is set to '{0}' and the history "
                "contains '{0}_best'. Perhaps you meant to set the parameter "
                "to '{0}_best'".format(self.monitor), UserWarning)

        if self.monitor is None:
            do_checkpoint = True
        elif callable(self.monitor):
            do_checkpoint = self.monitor(net)
        else:
            try:
                do_checkpoint = net.history[-1, self.monitor]
            except KeyError as e:
                raise SkorchException(
                    "Monitor value '{}' cannot be found in history. "
                    "Make sure you have validation data if you use "
                    "validation scores for checkpointing.".format(e.args[0]))

        if self.event_name is not None:
            net.history.record(self.event_name, bool(do_checkpoint))

        if do_checkpoint:
            self.save_model(net)
            self._sink("A checkpoint was triggered in epoch {}.".format(
                len(net.history) + 1
            ), net.verbose)

def on_epoch_end(self, net, **kwargs):
        if self.monitor is None:
            do_checkpoint = True
        elif callable(self.monitor):
            do_checkpoint = self.monitor(net)
        else:
            try:
                do_checkpoint = net.history[-1, self.monitor]
            except KeyError as e:
                raise SkorchException(
                    "Monitor value '{}' cannot be found in history. "
                    "Make sure you have validation data if you use "
                    "validation scores for checkpointing.".format(e.args[0]))

        if do_checkpoint:
            target = self.target
            if isinstance(self.target, str):
                target = self.target.format(
                    net=net,
                    last_epoch=net.history[-1],
                    last_batch=net.history[-1, 'batches', -1],
                )
            if net.verbose > 0:
                print("Checkpoint! Saving model to {}.".format(target))
            net.save_params(target)