diff --git a/benchmark/Datasets.py b/benchmark/Datasets.py
index 20a4894..0150623 100644
--- a/benchmark/Datasets.py
+++ b/benchmark/Datasets.py
@@ -24,13 +24,12 @@ class DatasetsArff:
     def folder():
         return "datasets"
 
-    def load(self, name, class_name="class"):
+    def load(self, name, class_name):
         file_name = os.path.join(self.folder(), self.dataset_names(name))
         data = arff.loadarff(file_name)
         df = pd.DataFrame(data[0])
-        y = df[class_name]
-        X = data.drop(class_name, axis=1).to_numpy()
-        y = data[class_name].to_numpy()
+        X = df.drop(class_name, axis=1).to_numpy()
+        y = df[class_name].to_numpy()
         return X, y
 
 
@@ -43,7 +42,7 @@ class DatasetsTanveer:
     def folder():
         return "data"
 
-    def load(self, name):
+    def load(self, name, _):
         file_name = os.path.join(self.folder(), self.dataset_names(name))
         data = pd.read_csv(
             file_name,
@@ -64,7 +63,7 @@ class DatasetsSurcov:
     def folder():
         return "datasets"
 
-    def load(self, name):
+    def load(self, name, _):
         file_name = os.path.join(self.folder(), self.dataset_names(name))
         data = pd.read_csv(
             file_name,
@@ -80,23 +79,38 @@ class DatasetsSurcov:
 
 class Datasets:
     def __init__(self, dataset_name=None):
+        default_class = "class"
         envData = EnvData.load()
         class_name = getattr(
             __import__(__name__),
             f"Datasets{envData['source_data']}",
         )
         self.dataset = class_name()
+        self.class_names = []
         if dataset_name is None:
             file_name = os.path.join(self.dataset.folder(), Files.index)
             with open(file_name) as f:
                 self.data_sets = f.read().splitlines()
+                self.class_names = [default_class] * len(self.data_sets)
+            if "," in self.data_sets[0]:
+                result = []
+                class_names = []
+                for data in self.data_sets:
+                    name, class_name = data.split(",")
+                    result.append(name)
+                    class_names.append(class_name)
+                self.data_sets = result
+                self.class_names = class_names
+
         else:
             self.data_sets = [dataset_name]
+            self.class_names = [default_class]
 
     def load(self, name):
         try:
-            return self.dataset.load(name)
-        except FileNotFoundError:
+            class_name = self.class_names[self.data_sets.index(name)]
+            return self.dataset.load(name, class_name)
+        except (ValueError, FileNotFoundError):
             raise ValueError(f"Unknown dataset: {name}")
 
     def __iter__(self) -> Diterator:
diff --git a/benchmark/__init__.py b/benchmark/__init__.py
index cac5b02..e26a7cf 100644
--- a/benchmark/__init__.py
+++ b/benchmark/__init__.py
@@ -1,4 +1,4 @@
-from .Datasets import Datasets, DatasetsSurcov, DatasetsTanveer
+from .Datasets import Datasets, DatasetsSurcov, DatasetsTanveer, DatasetsArff
 from .Experiments import Experiment
 from .Results import Report, Summary