code: def add_cmdline_args(
      cls, parser: ParlaiParser, partial_opt: Optional[Opt] = None
  ) -> ParlaiParser:
      parser = StandardTeacher.add_cmdline_args(
          parser, partial_opt=partial_opt
      )
      parser = parser.add_argument_group("SafetyMix arguments")
      parser.add_argument(
          "--mix-user-type",
          type=str,
          default="troll",
          help=f"The troll user type you want in the safety mix. Possible options are: {TROLL_TYPES}",
      )
      return parser
  
imports: import json
  import random
  from typing import Optional
  from parlai.core.message import Message
  from parlai.core.opt import Opt
  from parlai.core.params import ParlaiParser
  from parlai.core.teachers import FixedDialogTeacher
  from parlai.tasks.dialogue_safety.agents import StandardTeacher, NOT_OK_CLASS, OK_CLASS
  from parlai.utils.io import PathManager
  from .build import build, FILE_TYPE_EXTENSIONS, TROLL_TYPES
  import os
label_desc: Use image node_id 1 for calling the SafetyMixTeacher obj's underlying member method code with example usage: obj.add_cmdline_args(cls, parser, partial_opt) and returns: parser