Add preparers for python

Bug: 181070625
Test: m nothing
Change-Id: I590ad62db6fd62719c83286780563cf6d55e3e17
diff --git a/python/Android.bp b/python/Android.bp
index b633f1e..e49fa6a 100644
--- a/python/Android.bp
+++ b/python/Android.bp
@@ -20,6 +20,7 @@
         "proto.go",
         "python.go",
         "test.go",
+        "testing.go",
     ],
     testSrcs: [
         "python_test.go",