code: def on_epoch_begin(self, epoch_number: int, logs: dict):
      self.metric.current_epoch = epoch_number
  
imports: import unittest
  import torch
  import torch.nn
  from poutyne import Callback, EarlyStopping, Metric, Model
  from tests.framework.base import CaptureOutputBase
  from tests.framework.tools import some_data_generator
label_desc: Use image node_id 2 for calling the DummyMetricCallback obj's underlying member method code with example usage: obj.on_epoch_begin(epoch_number, logs) without return types