keras/src/callbacks/callback.py/Callback/on_train_batch_end
class Callback:    def on_train_batch_end(self, batch, logs=None):
        """Called at the end of a training batch in `fit` methods.

        Subclasses should override for any actions to run.

        Note that if the `steps_per_execution` argument to `compile` in
        `Model` is set to `N`, this method will only be called every
        `N` batches.

        Args:
            batch: Integer, index of batch within the current epoch.
            logs: Dict. Aggregated metric results up until this batch.
        """
        # For backwards compatibility.
        self.on_batch_end(batch, logs=logs)