class_docstr: Mock Dictionary Agent which just implements indexing and txt2vec.
class_docstr_tok: ["Mock","Dictionary","Agent","which","just","implements","indexing","and","txt2vec","."]
docstr: Initialize idx for incremental indexing.
docstr_tok: ["Initialize","idx","for","incremental","indexing","."]
code: def __init__(self, opt, shared=None):
      """
      Initialize idx for incremental indexing.
      """
      self.idx = 0
  
imports: from typing import Optional
  from parlai.core.params import ParlaiParser
  from parlai.core.opt import Opt
  from parlai.core.torch_agent import TorchAgent, Output
  import torch
  from parlai.core.agents import Agent
label_desc: Use image node_id 1 to create a new MockDict object from inherited base classes: Agent with example: obj = MockDict(opt, shared)