recv(timeout=2) raising the exception: ord() expected a character, but string of length 0 found.

[ghost]

Hi, I'm using a Seeedstudio USB-CANalyzer interface with a bitrate of 500,000. I am communicating with a battery that uses extended arbitration ID. I want to know how long does it take for my battery to enter Sleep Mode (stop sending CAN messages). Hence I am using the next code:

Currently I have let my script run but randomly I would get the next exception raised.

Exception has occurred:
TypeError
ord() expected a character, but string of length 0 found
line 29, in main
msg = Bus.recv(timeout=2)
TypeError: ord() expected a character, but string of length 0 found

The manufacturer comments the time to enter sleep mode, if the battery is not in use, is a bit longer than 2 hours. Altough I could come around with a quick fix or just assume manufacturer is correct, I wonder if there is something I am skipping or I should consider to understand better this error.

Thank you!

[grant-allan-ctct]

It's interesting to see the comment here that ser.read can return an empty string, and yet this possibility is seemingly not catered for in various places, e.g. on lines 259 or 280.