There are a number things that might be going on.
the code wouldn't even upload when I used their sketch.
I assume you mean the Arduino sketch. There is some nonsense in the link. Your code is using hardware serial. This is fine but it is shared with the USB cable and the fact that you have this problem more or less confirms this - and that you have the right port configured, but you cannot upload with bluetooth connected. Solution: disconnect. You can do this by taking out the port selection jumpers.
No comment on Python per se, but does it work with cable connect? If so, it is probably just a matter of changing the COM port. Your bluetooth sniffer or Control panel should advise you of the correct port for PC's Bluetooth.
If Arduino code works via cable, there is no need to change it.