code: def on_epoch_end(self):
      if not self.data.data:
          return
      tracker.add(f"{self.name}.", torch.cat(self.data.data, dim=0))
  
file_path: labml/helpers/labml_helpers/metrics/collector.py
imports: import dataclasses
  from typing import List
  import torch
  from labml import tracker
  from .None import Metric
label_desc: Use image node_id 6 for calling the Collector obj's underlying member method code with example usage: obj.on_epoch_end() without return types