[2.13+3.0] Use string startswith() and endswith() methods
... instead of slicing to check for prefixes and suffixes.
This change prevents a crash in aa-mergeprof - if replacement
is empty,
trying to access replacement[0]
causes an IndexError.
Using .startswith()
works without crashing.
This backports parts of the severity.py changes in commit 091c6ad5 by Mark Grassi.
I propose this fix for 2.13 and 3.0. (3.1 and master already have this fix.)