diff --git a/core/input.py b/core/input.py
index cc450c7..fce461e 100644
--- a/core/input.py
+++ b/core/input.py
@@ -38,7 +38,7 @@ def __invoke(event, callback):
     if not callback: return
     if not 'button' in event: return
 
-    for cb in callback.get(event['button']):
+    for cb in callback.get(event['button'], []):
         if callable(cb):
             cb(event)
         else:
diff --git a/tests/core/test_input.py b/tests/core/test_input.py
index e469543..8e68f4c 100644
--- a/tests/core/test_input.py
+++ b/tests/core/test_input.py
@@ -17,6 +17,11 @@ class config(unittest.TestCase):
         core.input.trigger(self.someEvent)
         self.callback.assert_called_once_with(self.someEvent)
 
+    def test_nonexistent_callback(self):
+        core.input.register(self.inputObject, self.someEvent['button'], self.callback)
+        core.input.trigger(self.anotherEvent)
+        self.callback.assert_not_called()
+
     def test_different_events(self):
         core.input.register(self.inputObject, self.someEvent['button'], self.callback)
         core.input.register(self.inputObject, self.anotherEvent['button'], self.callback)