Failure to read data yields a 0 instead of error or NoneType

[SWalt567]

I currently have 2 max3155 thermocouples amps on a raspberry pi. 1 amp is fully wired and has no thermocouple (intentional) and another has a thermocouple and faulty wiring on the MISO and SCLK pin (intentional) for the purpose of testing failures to read temperature data.

I'm using a script with an up-to-date version of this repo to record the temperature, expecting an error/None but instead getting a 0.

Script for reference:
`
class thermocouple():
""" thermocouple class

thermocouple class creates a connection to the probe,
and houses a generator that when called, returns/yields datetime,
temperature, and a status message. Under circumstances when
the thermocouple shorts, or has any other error, the message will contain
said error and flag the data so it wont be graphed.

ARGS:
    probe_id: each probe has its own CS/SS (chip select/slave select)
    pin, the probe_id will tell the class which CS/SS pin to assign it to
    spi:
    running:
"""
def __init__(self, probe_id, spi=None, running=False):

    if spi == None:
        spi = busio.SPI(board.D11, MOSI=board.MOSI)
    # create property to later return to other thermocouples
    self.__spi = spi

    # self.__cs = digitalio.DigitalInOut(board.D6) #previous solution

    cs_dict = {'probe1': digitalio.DigitalInOut(board.D5),
               'probe2': digitalio.DigitalInOut(board.D6),
               'probe3': digitalio.DigitalInOut(board.D13),
               'probe4': digitalio.DigitalInOut(board.D19)}

    try:
        self.__cs = cs_dict[probe_id]
        #print(probe_id+" 5" if probe_id=='probe1' else " 6")
    except KeyError:
        logger.critical('{} not found in cs_dict'.format(probe_id))
        # exit??

    # construct thermocouple object
    self.thermo = self.__thermo(self.__spi, self.__cs)
    if __name__ == "__main__":
        logger.debug("created {}".format(probe_id))

def __thermo(self, spi, cs):
    return adafruit_max31855.MAX31855(spi, cs)

@property
def spi(self):
    return self.__spi

@spi.setter
def spi(self, spi):
    self.__spi = spi
    self.thermo = __thermo(self.__spi, self.__cs)

def get_temperature(self):  # asks for current temp of thermocouple
    """
    yield `probe.temperature` (might have to be a return)
    """
    return self.thermo.temperature

def get_data(self):
    """
    call `temperature()` if possible

    get datetime,temperature,msg (msg would be "ok" or None)

    catch `RuntimeError` and yield None,msg

    if return_msg is True, return the two things
    """
    msg = 'ok'  # status message that will be returned when there is no error
    try:
        temp = self.get_temperature()
    except RuntimeError as m:  # calls for temperature and catches short errors instead of stopping
        msg = m
        temp = None
    utc = datetime.datetime.now()
    utc = utc.replace(tzinfo=from_zone)
    local = utc.astimezone(to_zone)
    return local, temp, msg

def yield_data(self):
    yield self.get_data()

`

Output after running:

0.0 probe1, DT: 2021-04-01 11:28:11.490445-08:00 T: 0.0 MSG: 'ok' 0.0 probe2, DT: 2021-04-01 11:28:11.493411-08:00 T: 0.0 MSG: 'ok'

I currently can't find any reason why I'm getting this output. Any feedback is appreciated :)