diff --git a/pysnippets/Memoisation/factorial.py b/pysnippets/Memoisation/factorial.py
index 5d5a77d..774f75e 100644
--- a/pysnippets/Memoisation/factorial.py
+++ b/pysnippets/Memoisation/factorial.py
@@ -1,6 +1,6 @@
 import logging
 from dataclasses import dataclass
-from pysnippets.Memoisation.decorator import memoize
+from decorator import memoize
 
 logging.basicConfig(level=logging.INFO)
 logger = logging.getLogger(__name__)
diff --git a/pysnippets/Memoisation/fibonacci.py b/pysnippets/Memoisation/fibonacci.py
index 4c57378..9461c23 100644
--- a/pysnippets/Memoisation/fibonacci.py
+++ b/pysnippets/Memoisation/fibonacci.py
@@ -1,6 +1,6 @@
 import logging
 from dataclasses import dataclass
-from pysnippets.Memoisation.decorator import memoize
+from decorator import memoize
 
 logging.basicConfig(level=logging.INFO)
 logger = logging.getLogger(__name__)
diff --git a/pysnippets/Memoisation/knapsack.py b/pysnippets/Memoisation/knapsack.py
index e2bbb9f..44f5410 100644
--- a/pysnippets/Memoisation/knapsack.py
+++ b/pysnippets/Memoisation/knapsack.py
@@ -1,12 +1,12 @@
 import logging
 from dataclasses import dataclass
-from pysnippets.Memoisation.decorator import memoize
-from typing import List, Tuple
+from decorator import memoize
+from typing import Tuple
 
 logging.basicConfig(level=logging.INFO)
 logger = logging.getLogger(__name__)
 
-@dataclass
+@dataclass(frozen=True)
 class Item:
     value: int
     weight: int