better cache cleanup

oml/cache.py

@@ -7,12 +7,12 @@ class Cache(dict):
         self._added = {}
 
     def get(self, key):
-        if key in self._added:
-            if self._added[key] < time.time():
+        now = time.time()
+        for key, value in self._added.items():
+            if value < now:
                 del self._added[key]
                 del self[key]
-                return
-            return dict.__getitem__(self, key)
+        return dict.get(self, key)
 
     def set(self, key, value, ttl=None):
         ttl = ttl or self._ttl