docstr: Add the output list subparser: manage.py output list [options]
docstr_tok: ["Add","the","output","list","subparser",":","manage.py","output","list","[","options","]"]
code: def setup_subparser(cls, subparser):
      """Add the output list subparser: manage.py output list [options]"""
      outputs = sorted(StreamAlertOutput.get_all_outputs().keys())
  
      list_parser = generate_subparser(
          subparser,
          "list",
          description=cls.description,
          help=cls.description,
          subcommand=True,
      )
  
      # Add the optional arg of service
      list_parser.add_argument(
          "--service",
          "-s",
          choices=outputs,
          default=outputs,
          nargs="*",
          metavar="SERVICE",
          help="Pass Services to list configured output descriptors, select from: {}".format(
              ", ".join(outputs)
          ),
      )
  
imports: import json
  from streamalert.shared.logger import get_logger
  from streamalert.alert_processor.outputs.output_base import StreamAlertOutput, OutputCredentialsProvider
  from streamalert_cli.helpers import user_input, response_is_valid
  from streamalert_cli.outputs.helpers import output_exists
  from streamalert_cli.utils import CLICommand, generate_subparser
label_desc: Use image node_id 1 for calling the OutputListSubCommand obj's underlying member method code with example usage: obj.setup_subparser(cls, subparser) without return types