--- subprocess.py	2016-03-03 10:44:12.000000000 +0100
+++ subprocess-mod.py	2016-05-12 12:43:09.055111439 +0200
@@ -655,6 +655,9 @@ class CompletedProcess(object):
             args.append('stderr={!r}'.format(self.stderr))
         return "{}({})".format(type(self).__name__, ', '.join(args))
 
+    def __bool__(self):
+        return self.returncode == 0
+
     def check_returncode(self):
         """Raise CalledProcessError if the exit code is non-zero."""
         if self.returncode: