avoid duplicated keys in nested queries

pandora/clip/managers.py

@@ -145,7 +145,11 @@ class ClipManager(Manager):
         keys = layer_ids + ['annotations', 'text', '*']
         conditions = data.get('query', {}).get('conditions', [])
         conditions = flatten_conditions(conditions)
-        conditions = list(filter(lambda c: c.get('key') in keys, conditions))
+        conditions_ = []
+        for c in conditions:
+            if c.get('key') in keys and c not in conditions_:
+                conditions_.append(c)
+        conditions = conditions_
         operator = data.get('query', {}).get('operator', '&')
 
         def parse(condition):