def before_training(self, strategy: "SupervisedTemplate"):
        """Performs actions before the training phase.

        :param strategy: The strategy object associated with the metric.
        """
        super().before_training(strategy)
        if self.num_training_steps is not None:
            self.num_training_steps += 1
        else:
            self.num_training_steps = 0
Performs actions before the training phase.

        :param strategy: The strategy object associated with the metric.
        
avalanche/evaluation/metrics/acc_matrix.py