diff -r ff72bd52d56a -r 9d2b2df2c2ba contrib/check-py3-compat.py
--- a/contrib/check-py3-compat.py	Fri Mar 06 10:52:44 2020 +0100
+++ b/contrib/check-py3-compat.py	Fri Mar 06 13:27:41 2020 -0500
@@ -32,7 +32,7 @@
     for node in ast.walk(root):
         if isinstance(node, ast.ImportFrom):
             if node.module == '__future__':
-                futures |= set(n.name for n in node.names)
+                futures |= {n.name for n in node.names}
         elif isinstance(node, ast.Print):
             haveprint = True