Branch following issues

[thatch]

None of these are handled well (it assumes all branches are followed, and you'd need to --allow-names both or only test on one and --allow-names the other.

try:
  import x
except ImportError:
  import y

if sys.version_info < (3, 8):
  import x
else:
  import y

try:
  import x
except ImportError:
  x = None