individual get_sms gives 'IndexError: list index out of range' Python 3.9

[ghost]

Getting really odd behaviour with the get_sms() function.

[GCC 10.2.1 20210110] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from sim_modem import Modem
>>> modem = Modem('/dev/ttyUSB3')
>>> modem_id = modem.get_model_identification()
>>> print(modem_id)
SIMCOM_SIM7600G-H
>>> sms = modem.get_sms(0)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python3.9/dist-packages/sim_modem.py", line 655, in get_sms
    "slot": read[1].split(":")[1].split(",")[0].strip(),
IndexError: list index out of range
>>> sms = modem.get_sms(1)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python3.9/dist-packages/sim_modem.py", line 655, in get_sms
    "slot": read[1].split(":")[1].split(",")[0].strip(),
IndexError: list index out of range

When I add the debug output (I've obviously redacted the phone number - but that is all I have done):

>>> modem = Modem('/dev/ttyUSB3', baudrate="115200", debug=True)
Modem connected, debug mode enabled
>>> sms = modem.get_sms_list()
Sending: AT+CMGF=1
Sending: AT+CMGL="ALL"
Device responded:  ['AT+CMGF=1', 'OK', 'AT+CMGL="ALL"', '+CMGL: 0,"REC READ","+************ ","","23/07/29,05:01:03+04"', '3rd Test Message Sent', '+CMGL: 1,"REC READ","+************ ","","23/07/29,05:04:04+04"', '4th test sms... this has to work', '+CMGL: 2,"REC READ","+************ ","","23/07/29,05:10:02+04"', "5th test. PLEASE python don't fail me now.", '+CMGL: 3,"REC READ","+************ ","","23/07/29,05:23:57+04"', "6th, this is a tad annoting why the code isn't working properly", '+CMGL: 4,"REC READ","+************ ","","23/07/29,05:30:17+04"', 'possibly final test for today', '', 'OK']
>>> sms = modem.get_sms(1)
Sending: AT+CMGF=1
Sending: AT+CMGR=1
Device responded:  ['AT+CMGF=1', 'OK', 'AT+CMGR=1', '+CMGR: "REC READ","+************ ","","23/07/29,05:04:04+04"', '4th test sms... this has to work', '', 'OK']
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python3.9/dist-packages/sim_modem.py", line 655, in get_sms
    "slot": read[1].split(":")[1].split(",")[0].strip(),
IndexError: list index out of range

I can't decipher all the splits in the return section:

return {
            "slot": read[1].split(":")[1].split(",")[0].strip(),
            "number": read[1].split('READ","')[1].split('","","')[0],
            "date": read[1].split('","","')[1].split(",")[0],
            "time": read[1].split(",")[5].split("+")[0],
            "message": read[4].replace("\r\n", "").strip(),
        }

The kind of TL;DR is is does read the SMS from the module, but it seems, in python 3.9 at least, the convertion to a dict for the output no longer works as expected...

Firmware of module is: LE20B03SIM7600M22 (not that I can find much by way of reliable info on any newer versions - I'm not daft enough to download files from random website!)

[ghost]

I'm going to assume this is either difference in SIMCOM module firmware, or a slight variation of module meaning different AT outputs?

When using get_sms() the return of a slot value doesn't make much sense as you entered it into the function so returning it seems redundant.

So unless I'm really hugely missing something if I edit the return filters to be:

## output from modules AT command
read=['AT+CMGF=1', 'OK', 'AT+CMGR=1', '+CMGR: "REC READ","+************ ","","23/07/29,05:04:04+04"', '4th test sms... this has to work', '', 'OK']

return {
    "number": read[3].split(",")[1].strip('"'),
    "date": read[3].split(",")[3].strip('"'),
    "time": read[3].split(",")[4].split("+")[0],
    "message": read[4],
}

It should work with the AT outputs from my SIM7600G-H. I've only tested roughly will do more.