Raise an error for unsupported hook event

* Raises a ValueError for an unsupported hook event

1 files changed, 3 insertions, 0 deletions

diff --git a/requests/models.py b/requests/models.py
index 6b4a2994..007a9f1c 100644
--- a/requests/models.py
+++ b/requests/models.py
@@ -141,6 +141,9 @@ class RequestHooksMixin(object):
     def register_hook(self, event, hook):
         """Properly register a hook."""
 
+        if event not in self.hooks:
+            raise ValueError('Unsupported event specified, with event name "%s"' % (event))
+
         if isinstance(hook, collections.Callable):
             self.hooks[event].append(hook)
         elif hasattr(hook, '__iter__'):