Fix exception handling for the import of essential modules

[elfring]

The script “guider.py” contains the following source code at the moment.

…
try:
…
    import sys
…

I doubt that the specified exception handling can work if the mentioned statement failed. 🤔

…
except ImportError:
    err = sys.exc_info()[1]
…

[iipeace]

@elfring You are right!
It can be shown strange logically,
But I think it is impossible to fail to import sys module in python :)

[elfring]

How do you think about to split the affected code so that it will be correct? 🤔

[iipeace]

@elfring I agree with you!
I'll split them :)