We know that the BDFL said Python will no more have a release that will break the retrocompatibility. So no Python 4.
But what if a Python 4 will be released, in an alternative Earth in the multiverse?
In my top list, there’s the implicit sum between adjacent strings:
myfunc(
"Hello!",
"Here a missed a colon"
"and spent many hours and bad words to debug",
"Damned C."
)
That’s a very good feature, and it’s only a problem when you’re in a context where you’re laying things out with commas. Fortunately, a number of linters will catch that, so you don’t need an alternative universe - just a better editor or toolchain 
Well, it was a good feature in C, and questionable good feature for Python until the multiline strings was not part of the language. But I never understood what a plus added in plus can hurt so much.
Another fact that make me crazy is the possibility to write a tuple with a single element with only a comma:
a = 1,
instead of a more readable and explicit:
a = (1, )
One time I spent a day to understand why sqlalchemy did not work. It was a comma that I put by error at the end of a parameter. I pondered about removing the comma from the keyboard.
PS: I have PyCharm, but I don’t use it very often. I find using a simple text editor as Sublime more fast.
PPS: I really need an alternative universe, with blackjack and… you know.
Srting abuttal is NOT the same as multiline strings.
Can you PLEASE go and do some research before posting another off-the-wall idea? Actually go and try things out?
So:
("Hello \n" +
"World")
("Hello \n"
"World")
and
"""Hello
World"""
have not the same result?
Furthermore, you’re bit off topic. The topic is about what if a Python 4 comes up. What breaking change would you have?
I would not. It is that simple. Breaking changes are bad and need a lot more justification than “hey, let’s change a version number and have fun causing problems for the entire world”.
Thanks for your sharing your POV, but the thread is about an highly hypothetical Python 4.
Furthermore, can you reply me to this?