class_docstr: Label is the speaker.
  
  Left to right (partial sequences)
class_docstr_tok: ["Label","is","the","speaker",".","Left","to","right","(","partial","sequences",")"]
code: def __init__(self, opt, shared=None):
      opt["speaker_label_type"] = "speaker"
      opt["left_to_right"] = True
      super().__init__(opt, shared)
  
imports: from abc import ABC
  from collections import deque
  import re
  from typing import Optional
  from parlai.core.build_data import modelzoo_path
  from parlai.core.message import Message
  from parlai.core.metrics import AverageMetric
  from parlai.core.opt import Opt
  from parlai.core.params import ParlaiParser
  from parlai.tasks.light_dialog.agents import SimpleMultiTeacher
  from parlai.utils.data import DatatypeHelper
  import parlai.utils.logging
  import copy
  import os
  import random
  import torch
  import torch.nn
  import torch.nn.functional
  from typing import List, Dict, Tuple
  from projects.light_whoami.task.utils import DEFAULT_DELIM, CONTEXT_KEYS, extract_characters, WHO_AM_I, WHO_ARE_YOU, SELF, PARTNER, WHO_IS_THIS, maybe_annotate
  import projects.light_whoami.task.mutators
label_desc: Use image node_id 1 to create a new WhoIsSpeakingLeftToRightTeacher object from inherited base classes: SpeakerClassifierTeacher with example: obj = WhoIsSpeakingLeftToRightTeacher(opt, shared)