I'm not talking about changing the type of the exception, Serhiy. but only to make the text message more explicit by adding a lead to a secondary possible cause. I do not understand how this addition would be misleading - more than the case I presented ? (Did you check my example ?)

I agree that this message might possibly make my mistake obvious to an senior _python_ programmer, but doesn't the constraint of being _experienced in python_, not go in contradiction with the mantra "Explicit is better than implicit" ?