SF 563203. Replaced 'has_key()' with 'in'.
diff --git a/Lib/zipfile.py b/Lib/zipfile.py
index 4e7ea10..c0a0fe5 100644
--- a/Lib/zipfile.py
+++ b/Lib/zipfile.py
@@ -354,7 +354,7 @@
 
     def _writecheck(self, zinfo):
         """Check for errors before writing a file to the archive."""
-        if self.NameToInfo.has_key(zinfo.filename):
+        if zinfo.filename in self.NameToInfo:
             if self.debug:      # Warning for duplicate names
                 print "Duplicate name:", zinfo.filename
         if self.mode not in ("w", "a"):