Use PyContracts so we can declare/enforce parameter and return types.

This commit doesn't add any uses of PyContracts, but gets the machinery in
place.

1 files changed, 1 insertions, 0 deletions

diff --git a/tox.ini b/tox.ini
index 37ae451f..69d94a0a 100644
--- a/tox.ini
+++ b/tox.ini
@@ -26,6 +26,7 @@ commands =
 deps =
     nose
     mock
+    PyContracts
     py26: unittest2
     py26,py27: gevent
     py26,py27: eventlet