code: def main():
      """Entry point for ``python -m mpi4py.futures ...``."""
      # pylint: disable=import-outside-toplevel
      import os
      import sys
      from ..run import run_command_line
      from ..run import set_abort_status
      from ._core import SharedPoolCtx
  
      class UsageExit(SystemExit):
          # pylint: disable=missing-class-docstring
          pass
  
      def usage(error=None):
          from textwrap import dedent
  
          python = os.path.basename(sys.executable)
          program = __spec__.parent
          usage = dedent(
              f"""
          usage: {python} -m {program} <pyfile> [arg] ...
             or: {python} -m {program} -m <module> [arg] ...
             or: {python} -m {program} -c <string> [arg] ...
          """
          ).strip()
          if error:
              print(error, file=sys.stderr)
              print(usage, file=sys.stderr)
          else:
              print(usage, file=sys.stdout)
          raise UsageExit(1 if error else 0)
  
      def chk_command_line():
          args = sys.argv[1:]
          if not args:
              usage("No path specified for execution")
          elif args[0] == "-":
              pass
          elif args[0] in ("-h", "--help"):
              usage()
          elif args[0] in ("-m", "-c"):
              if len(args) < 2:
                  usage(f"Argument expected for option: {args[0]}")
          elif args[0].startswith("-"):
              usage(f"Unknown option: {args[0]}")
          elif not os.path.exists(args[0]):
              usage(f"Path does not exist: {args[0]}")
  
      try:
          with SharedPoolCtx() as context:
              if context is not None:
                  chk_command_line()
                  run_command_line()
      except UsageExit:
          raise
      except SystemExit as exc:
          set_abort_status(exc)
          raise
      except KeyboardInterrupt as exc:
          set_abort_status(exc)
          raise
      except BaseException:
          set_abort_status(1)
          raise
  
label_desc: Use image node_id 1 for calling a global function with example usage: main() without return types