Loosen type hint on cleanIntermediate

Author: keysmashes

cwltool/process.py

@@ -375,7 +375,7 @@ def relink(relinked,  # type: Dict[Text, Text]
     return outputObj
 
 
-def cleanIntermediate(output_dirs):  # type: (Set[Text]) -> None
+def cleanIntermediate(output_dirs):  # type: (Iterable[Text]) -> None
     for a in output_dirs:
         if os.path.exists(a):
             _logger.debug(u"Removing intermediate output directory %s", a)