string to list and back again as same type

[Gribouillis]

One thing to consider is that with [0:0], you'll join with the empty string instead of a space character. That's why I introduced the _joinchar dictionary.

There is still a missing feature in my code above: it doesn't handle the case of user defined subclasses of the builtin string types. A generic function should solve this issue, that is to say code from_list() with functools.singledispatch().