Add note on exception case
@@ -91,6 +91,8 @@ class BranchCoverageInstrumentation(Instrumentation):
# As of CPython 3.8, there are a few compare ops for which we can't really
# compute a sensible branch distance. So for now, we just ignore those
# comparisons and just track their boolean value.
+ # As of CPython 3.9, this is no longer a compare op but instead
+ # a JUMP_IF_NOT_EXC_MATCH, which we also handle as boolean based jump.
_IGNORED_COMPARE_OPS: Set[Compare] = {Compare.EXC_MATCH}
# Conditional jump operations are the last operation within a basic block
