Review [C] processing

@brief    Command-line entry point: python3.13 -m upper_tester --device /dev/quectel_at --port 12100

@details  Opens the modem, sends `ATE0` once (disable command echo so lines can be told

          apart from responses), and serves the upper-tester TCP protocol (see server.py)

          until interrupted (Ctrl-C), at which point the modem is reset (AT+CFUN=1,1)

          before the device is closed, so it isn't left in whatever state the last

          in-flight AT command left it in.

          until interrupted (Ctrl-C), at which point the modem is re-initialized

          (AT+CFUN=1, full functionality, *no* reset flag) before the device is closed,

          so it isn't left in whatever state the last in-flight AT command left it in

          (e.g. CFUN=0/4 from a MODEM_RESTART or DEREGISTER MMI command). This

          deliberately does not use AT+CFUN=1,1 (module reset): on Quectel modules

          that reboots the cellular/USB subsystem, which drops and re-enumerates the

          ttyUSB device -- on the Pi that meant /dev/ttyUSB2 could vanish for the

          ~15 s the module takes to come back, and a relaunch before then would fail

          to open it. AT+CFUN=1 changes RF functionality only; the USB link is

          untouched.

"""

import argparse

import asyncio

    try:

        asyncio.run(run())

    except KeyboardInterrupt:

        log.info("Ctrl-C received: resetting the modem before exit")

        log.info("Ctrl-C received: re-initializing the modem before exit")

        try:

            ok, text = modem.execute("AT+CFUN=1,1")

            log.info("AT+CFUN=1,1 -> %s %r", ok, text)

            # AT+CFUN=1, not AT+CFUN=1,1: restore full functionality without a module reset,

            # which would reboot the cellular/USB subsystem and drop the ttyUSB device (see

            # the module docstring).

            ok, text = modem.execute("AT+CFUN=1")

            log.info("AT+CFUN=1 -> %s %r", ok, text)

        except OSError as e:

            log.error("modem reset on exit failed: %s", e)

            log.error("modem re-initialization on exit failed: %s", e)

    finally:

        modem.close()