code: def on_epoch_begin(self, **kwargs):
          "Initialize the metrics for this epoch."
          self.metrics = {name:0. for name in self.names}
          self.nums = f on_epoch_begin(self, **kwargs):
          "Initialize the metrics for this epoch."
          self.metrics = {name:0. for name in self.names}
          self.nums = 0
docs: Initialize the metrics for this epoch.