class_docstr: E2E module.
  
  :param List idims: List of dimensions of inputs
  :param int odim: dimension of outputs
  :param Namespace args: argument Namespace containing options
docstr: Add arguments for encoders in multi-encoder setting.
code: def encoder_add_arguments(parser):
      """Add arguments for encoders in multi-encoder setting."""
      group = parser.add_argument_group("E2E encoder setting")
      group.add_argument(
          "--etype",
          action="append",
          type=str,
          choices=[
              "lstm",
              "blstm",
              "lstmp",
              "blstmp",
              "vgglstmp",
              "vggblstmp",
              "vgglstm",
              "vggblstm",
              "gru",
              "bgru",
              "grup",
              "bgrup",
              "vgggrup",
              "vggbgrup",
              "vgggru",
              "vggbgru",
          ],
          help="Type of encoder network architecture",
      )
      group.add_argument(
          "--elayers",
          type=int,
          action="append",
          help="Number of encoder layers "
          "(for shared recognition part in multi-speaker asr mode)",
      )
      group.add_argument(
          "--eunits",
          "-u",
          type=int,
          action="append",
          help="Number of encoder hidden units",
      )
      group.add_argument(
          "--eprojs",
          default=320,
          type=int,
          help="Number of encoder projection units",
      )
      group.add_argument(
          "--subsample",
          type=str,
          action="append",
          help="Subsample input frames x_y_z means "
          "subsample every x frame at 1st layer, "
          "every y frame at 2nd layer etc.",
      )
      return parser
  
imports: import argparse
  import logging
  import math
  import os
  from itertools import groupby
  import chainer
  import numpy
  import torch
  from chainer import reporter
  from espnet.nets.asr_interface import ASRInterface
  from espnet.nets.e2e_asr_common import label_smoothing_dist
  from espnet.nets.pytorch_backend.ctc import ctc_for
  from espnet.nets.pytorch_backend.nets_utils import get_subsample, pad_list, to_device, to_torch_tensor
  from espnet.nets.pytorch_backend.rnn.attentions import att_for
  from espnet.nets.pytorch_backend.rnn.decoders import decoder_for
  from espnet.nets.pytorch_backend.rnn.encoders import Encoder, encoder_for
  from espnet.nets.scorers.ctc import CTCPrefixScorer
  from espnet.utils.cli_utils import strtobool
label_desc: Use image node_id 2 for calling the E2E obj's underlying member method code with example usage: obj.encoder_add_arguments(parser) and returns: parser