No the intent here is to have flow like

if arg_suffix.endswith(SOURCE_SUFFIXES + BITCODE_SUFFIXES + DYNAMICLIB_SUFFIXES + ASSEMBLY_SUFFIXES) or shared.Building.is_ar(arg):
  xxx
elif arg_suffix.endswith(STATICLIB_SUFFIXES):
  yyy
else:
  zzz

The test for if os.path.exists(arg) was hoisted above, so the bulk of the code got a lower indent.