local variable 'option' referenced before assignment

[Gribouillis]

I never understood the code statement "while true". While what is true?

In python, true is written True with a capital T. The while True idiom means loop indefinitely. It may seem strange but it's simple logic: a while condition: loop runs until the condition becomes false. The True condition never becomes false, so while True loops indefinitely, without the need to add a new keyword such as repeat in the language.

C programmers traditionally write while(1) to loop indefinitely. This is the ancestor of python's while True. The latter is cleaner from a purist's point of view because a condition is a boolean rather than an integer. However even python uses 1 for True and 0 for False, for example

>>> True + 1
2

but

>>> True is 1
False