How to "tee" (=split) output to screen and into file?

[Gribouillis]

The wheel has already been invented, and so has logging!

This is true of course and in general, it is probably better to log than to print. However there is a little difference: in the logging system, you emit logging 'records', there is no way to use the exact semantics of the print() function with its sep and end and flush arguments. So the print function not only outputs information, it also formats the information with lower level details. I don't know how you could plug this semantics to the logging system.