How to assign a module to a variable even if it's not defined?

[snippsat]

The terms say that I come back if I find the solution. I use 'exec' to create a variable from string.

Yes,but a better way could be to use a data structure like dictionary.
What's really happens when do exec("abc=123") or just abc = 123,is that Python map this to a internal global dictionary.

>>> exec("abc = 123")
>>> globals()['abc']
123
>>> type(globals())
<class 'dict'>

So the way to make this more clear is to use real visible dictionary.

>>> d = dict(abc=123, foo=456)
>>> d
{'abc': 123, 'foo': 456}
>>> d['abc']
123

# Then also get method like get
>>> d.get('abc', 'Not in record')
123
>>> d.get('abcd', 'Not in record')
'Not in record'
>>> d.get('foo', 'Not in record')
456

Bye, I will make effort next time, I will try to be perfect

To be perfect is a goal we all will fail at
I think just a little expatiation of the goal of doing this was the point here.