class_docstr: Provide an opt-producer and CLI argument parser.
  
  Pseudo-extension of ``argparse`` which sets a number of parameters
  for the ParlAI framework. More options can be added specific to other
  modules by passing this object and calling ``add_arg()`` or
  ``add_argument()`` on it.
  
  For an example, see ``parlai.core.dict.DictionaryAgent.add_cmdline_args``.
  
  :param add_parlai_args:
      (default True) initializes the default arguments for ParlAI
      package, including the data download paths and task arguments.
  :param add_model_args:
      (default False) initializes the default arguments for loading
      models, including initializing arguments from that model.
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docstr: Pull in CLI args for proper models/tasks/etc.
  
  Called before args are parsed; ``_load_opts`` is used for actually overriding
  opts after they are parsed.
docstr_tok: ["Pull","in","CLI","args","for","proper","models\/tasks\/etc",".","Called","before","args","are","parsed",";","``","_load_opts","``","is","used","for","actually","overriding","opts","after","they","are","parsed","."]
code: def _load_known_opts(self, optfile, parsed):
      """
      Pull in CLI args for proper models/tasks/etc.
  
      Called before args are parsed; ``_load_opts`` is used for actually overriding
      opts after they are parsed.
      """
      new_opt = Opt.load_init(optfile)
      for key, value in new_opt.items():
          # existing command line parameters take priority.
          if key not in parsed or parsed[key] is None:
              parsed[key] = value
  
imports: import argparse
  import importlib
  import os
  import sys
  import datetime
  import parlai
  import parlai.utils.logging
  from parlai.core.build_data import modelzoo_path
  from parlai.core.loader import load_teacher_module, load_agent_module, load_world_module
  from parlai.tasks.tasks import ids_to_tasks
  from parlai.core.opt import Opt
  from parlai.utils.io import PathManager
  from typing import List, Optional
label_desc: Use image node_id 17 for calling the ParlaiParser obj's underlying member method code with example usage: obj._load_known_opts(optfile, parsed) without return types