I noticed that the machine.RTC.datetime() is behaving stragely.

MicroPython v1.19.1-292-g59e3348c1-dirty on 2022-08-19; Arduino Nano RP2040 Connect with RP2040
>>> import machine
>>> machine.RTC.datetime()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: function missing 1 required positional arguments

I'm assuming that this function is supposed to return the currently stored date/time information in the RTC if no arguments are given and save date/time information in the RTC if an argument is given. It seems like it always requires an argument.

>>> machine.RTC.datetime((0, 0, 0, 0, 0, 0, 0, 0))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: argument has wrong type

If I give it some random date/time info, it just raises a TypeError. (same for lists)
Looking at the source code though , it seems strange: (machine_rtc.c)
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(machine_rtc_datetime_obj, 1, 2, machine_rtc_datetime);
It seems like this function requires one or two arguments.

STATIC mp_obj_t machine_rtc_datetime(mp_uint_t n_args, const mp_obj_t *args) {
    if (n_args == 1) { //shouldn’t this be n_args == 0 ?
        bool ret;
        datetime_t t;
        ...

I changed the entire function definition to:

STATIC mp_obj_t machine_rtc_datetime(mp_uint_t n_args, const mp_obj_t *args) {
    if (n_args == 0) {
        bool ret;
        datetime_t t;

        ret = rtc_get_datetime(&t);
        if (!ret) {
            mp_raise_OSError(MP_EIO);
        }

        mp_obj_t tuple[8] = {
            mp_obj_new_int(t.year),
            mp_obj_new_int(t.month),
            mp_obj_new_int(t.day),
            mp_obj_new_int(t.dotw),
            mp_obj_new_int(t.hour),
            mp_obj_new_int(t.min),
            mp_obj_new_int(t.sec),
            mp_obj_new_int(0)
        };

        return mp_obj_new_tuple(8, tuple);
    } else {
        mp_obj_t *items;

        mp_obj_get_array_fixed_n(args[0], 8, &items); //args[0] - first argument (list/tuple)

        datetime_t t = {
            .year = mp_obj_get_int(items[0]),
            .month = mp_obj_get_int(items[1]),
            .day = mp_obj_get_int(items[2]),
            .hour = mp_obj_get_int(items[4]),
            .min = mp_obj_get_int(items[5]),
            .sec = mp_obj_get_int(items[6]),
        };
        // Deliberately ignore the weekday argument and compute the proper value
        t.dotw = timeutils_calc_weekday(t.year, t.month, t.day);

        if (!rtc_set_datetime(&t)) {
            mp_raise_OSError(MP_EINVAL);
        }

    }
    return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(machine_rtc_datetime_obj, 0, 1, machine_rtc_datetime);

This fixes the first problem. Calling machine.RTC.datetime() will return a tuple with some default date/time info. However, calling it with an 8-tuple will raise the same TypeError as above.