Patch #1517891: Make 'a' create the file if it doesn't exist.
Fixes #1514451.
diff --git a/Misc/NEWS b/Misc/NEWS
index 06ffc16..c6d3831 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -128,6 +128,9 @@
 Library
 -------
 
+- Patch #1517891: Mode 'a' for ZipFile now creates the file if it
+  doesn't exist.
+
 - Patch #698833: Support file decryption in zipfile.
 
 - Patch #685268: Consider a package's __path__ in imputil.