code: def gen_mention_id(self) -> str:
      if (
          self.doc_id
          and self.sent_id is not None
          and self.tokens_number
      ):
          tokens_ids = [str(self.doc_id), str(self.sent_id)]
          tokens_ids.extend(
              [str(token_id) for token_id in self.tokens_number]
          )
          return "_".join(tokens_ids)
  
      return "_".join(self.tokens_str.split())
  
file_path: nlp-architect/nlp_architect/common/cdc/mention_data.py
imports: import sys
  from typing import List
  from nlp_architect.utils.io import load_json_file
  from nlp_architect.utils.string_utils import StringUtils
label_desc: Use image node_id 5 for calling the MentionData obj's underlying member method code with example usage: obj.gen_mention_id() and returns: str, str