diff --git a/PIL/OleFileIO.py b/PIL/OleFileIO.py
index c1cc5d5b6..978a4c3f7 100755
--- a/PIL/OleFileIO.py
+++ b/PIL/OleFileIO.py
@@ -339,10 +339,8 @@ VT_VECTOR=0x1000;
 
 # map property id to name (for debugging purposes)
 
-VT = {}
-for keyword, var in list(vars().items()):
-    if keyword[:3] == "VT_":
-        VT[var] = keyword
+VT = dict((var, keyword) for keyword, var in vars().items() if keyword[:3] == 'VT_')
+
 
 #
 # --------------------------------------------------------------------