fixed the way that keys is grabbed for redis

Author: Matias Melograno

splitio/storage/redis.py

@@ -87,7 +87,7 @@ def fetch_many(self, split_names):
         """
         to_return = dict()
         try:
-            keys = map(lambda split_name: self._get_key(split_name), split_names)
+            keys = [self._get_key(split_name) for split_name in split_names]
             raw_splits = self._redis.mget(keys)
             for i in range(len(split_names)):
                 split = None