diff --git a/cachalot/monkey_patch.py b/cachalot/monkey_patch.py
index 8ba7b4e..35df02b 100644
--- a/cachalot/monkey_patch.py
+++ b/cachalot/monkey_patch.py
@@ -59,14 +59,10 @@ def _get_result_or_execute_query(execute_query_func, cache_key,
         now = time()
         cache.set_many(dict([(k, now) for k in new_table_cache_keys]), None)
     elif cache_key in data:
-        try:
-            timestamp, result = data.pop(cache_key)
-        except TypeError:  # Occurs when None is unexpectedly found
-            pass
-        else:
-            table_times = data.values()
-            if table_times and timestamp > max(table_times):
-                return result
+        timestamp, result = data.pop(cache_key)
+        table_times = data.values()
+        if table_times and timestamp > max(table_times):
+            return result
 
     result = execute_query_func()
     if isinstance(result, Iterable) \
diff --git a/cachalot/transaction.py b/cachalot/transaction.py
index 6db017b..063b81f 100644
--- a/cachalot/transaction.py
+++ b/cachalot/transaction.py
@@ -11,18 +11,9 @@ class AtomicCache(dict):
         self.parent_cache = parent_cache
         self.to_be_invalidated = set()
 
-    def get(self, k, default=None):
-        if k in self:
-            return self[k]
-        return self.parent_cache.get(k, default)
-
     def set(self, k, v, timeout):
         self[k] = v
 
-    def add(self, k, v, timeout):
-        if self.get(k) is None:
-            self.set(k, v, timeout)
-
     def get_many(self, keys):
         data = dict([(k, self[k]) for k in keys if k in self])
         missing_keys = set(keys)