Update nibabel/externals/oset.py

Co-Authored-By: larsoner <[email protected]>

Author: effigies

nibabel/externals/oset.py

@@ -18,6 +18,7 @@
 try:
     from collections.abc import MutableSet
 except ImportError:
+    # PY2 compatibility
     from collections import MutableSet
 
 KEY, PREV, NEXT = range(3)
@@ -85,4 +86,4 @@ def __eq__(self, other):
         return set(self) == set(other)
 
     def __del__(self):
-        self.clear()                    # remove circular references
+        self.clear()                    # remove circular references