code: def handle_user_utt(
      self, message: Message, prefix_stripped_text: str
  ) -> Optional[Dict[str, Metric]]:
      self.done_seen |= STANDARD_DONE in message["text"]
      self.turn_count += 1
  
imports: from parlai.core.message import Message
  from parlai.core.metrics import Metric, AverageMetric
  from parlai.core.tod.tod_core import STANDARD_DONE
  from typing import Dict, List, Optional
label_desc: Use image node_id 2 for calling the UserGeneratedDoneMetricHandler obj's underlying member method code with example usage: obj.handle_user_utt(message, prefix_stripped_text) without return types