code: def fetch_command(self, subcommand):
          
          # Get commands outside of try block to prevent swallowing exceptions
          commands = get_commands()
          try:
              app_name = commands[subcommand]
          except KeyError:
              # This might trigger ImproperlyConfigured (masked in get_commands)
              settings.INSTALLED_APPS
              sys.stderr.write("Unknown command: %r\nType '%s help' for usage.\n" %
                  (subcommand, self.prog_name))
              sys.exit(1)
          if isinstance(app_name, BaseCommand):
              # If the command is already loaded, use it directly.
              klass = app_name
          else:
              klass = load_command_class(app_name, subcommand)
          return klass
docs: Tries to fetch the given subcommand, printing a message with the
          appropriate command called from the command line (usually
          "jira.py") if it can't be found.