diff --git a/preprocessing.py b/preprocessing.py
index 7cb8acd..afc1e7a 100644
--- a/preprocessing.py
+++ b/preprocessing.py
@@ -74,14 +74,30 @@ class DataSetSampling():
         self.sampling_strategy = sampling_strategy
         
     def fit(self, X):
-        return self
+        pass
     
     def transform(self):
-        return self
+        pass
     
     
 class Scaling():
     
+    def __init__(self, X, scaling_strategy):
+        self.X = X
+        self.scaler = scaling_strategy
+        
+    def fit(self, X):
+        pass
+    
+    def transform(self):
+        pass
+    
+    def fit_transform(self, X):
+        pass
+    
+    def inverse_transform(self, X):
+        pass
+