code: def add_subparser(
      self, parser: argparse._SubParsersAction
  ) -> argparse.ArgumentParser:
      description = """Count the number of training instances in an experiment config file."""
      subparser = parser.add_parser(
          self.name, description=description, help=description
      )
      subparser.add_argument(
          "param_path",
          type=str,
          help="path to an experiment config file",
      )
  
      subparser.add_argument(
          "-o",
          "--overrides",
          type=str,
          default="",
          help=(
              "a json(net) structure used to override the experiment configuration, e.g., "
              "'{\"vocabulary.min_count.labels\": 10}'.  Nested parameters can be specified either"
              " with nested dictionaries or with dot syntax."
          ),
      )
  
      subparser.set_defaults(func=count_instances_from_args)
  
      return subparser
  
imports: import argparse
  import logging
  from allennlp.commands.subcommand import Subcommand
  from allennlp.common.params import Params
label_desc: Use image node_id 1 for calling the CountInstances obj's underlying member method code with example usage: obj.add_subparser(parser) and returns: subparser