A change for Python 3.8—currently in beta—has produced some user-visible warnings, but the problem is often in code that a user cannot (or should not) change: third-party modules. The problem that the ...

is a new sequence starting as S[s] and ending at S[e-1]. S[e] isn’t included in the new sequence. That is, the new sequence is S[k] where s <= k <e. is the new sequence with elements S[1] and S[2].

A programmer who has put '\latex' as part of a string literal (to pick a not entirely random example) presumably actually wants '\\latex', which is what Python currently translates it to. This was a ...

No, it’s not a paradox or a contradiction. The tuple is immutable and you can’t change it after it is defined, but the need to modify a tuple, and other immutable sequences, is a common one. This ...