As an example, the socket module generates many different exceptions for various conditions, and they all are named "error". What makes each condition distinct lies in the exceptions details. The ...

To the MicroPython team’s credit, the socket module is a good copy of the desktop Python version, and you can get a very simple webserver coded up in a few lines, but that’s a few more lines ...

The only time to pickle something is if you need to represent a non-string object on disk, but Python code is strings. I presume that the receiving program is basically calling eval (skt.recv ()).