class_docstr: Concatenating embedding with float features before passing the input
  to DQN
code: def output_dim(self) -> int:
      return self._output_dim
  
file_path: ReAgent/reagent/models/embedding_bag_concat.py
imports: from typing import Dict, List
  import torch
  from reagent.core import types
  from reagent.core.utils import embedding_bag_configs_from_feature_configs
  from reagent.models.base import ModelBase
  from torchrec import EmbeddingBagConfig
label_desc: Use image node_id 2 for calling the EmbeddingBagConcat obj's underlying member method code with example usage: obj.output_dim() and returns: self