diff --git a/src/surfaces/test_functions/machine_learning/base_machine_learning_function.py b/src/surfaces/test_functions/machine_learning/base_machine_learning_function.py
index 868ccf4..8532768 100644
--- a/src/surfaces/test_functions/machine_learning/base_machine_learning_function.py
+++ b/src/surfaces/test_functions/machine_learning/base_machine_learning_function.py
@@ -7,5 +7,5 @@
 
 
 class MachineLearningFunction(BaseTestFunction):
-    def __init__(self, *args, **kwargs):
-        super().__init__(*args, **kwargs)
+    def __init__(self, metric, sleep, evaluate_from_data):
+        super().__init__(metric, sleep, evaluate_from_data)
diff --git a/src/surfaces/test_functions/machine_learning/tabular_classifiers.py b/src/surfaces/test_functions/machine_learning/tabular_classifiers.py
index afec37b..b555199 100644
--- a/src/surfaces/test_functions/machine_learning/tabular_classifiers.py
+++ b/src/surfaces/test_functions/machine_learning/tabular_classifiers.py
@@ -22,7 +22,7 @@ class KNeighborsClassifierFunction(MachineLearningFunction):
 
     def __init__(
         self,
-        metric="loss",
+        metric=None,
         sleep=0,
         evaluate_from_data=False,
     ):
diff --git a/src/surfaces/test_functions/machine_learning/tabular_regressors.py b/src/surfaces/test_functions/machine_learning/tabular_regressors.py
index 72b8c36..b74b10b 100644
--- a/src/surfaces/test_functions/machine_learning/tabular_regressors.py
+++ b/src/surfaces/test_functions/machine_learning/tabular_regressors.py
@@ -21,8 +21,13 @@ class KNeighborsRegressorFunction(MachineLearningFunction):
     cv_default = [2, 3, 4, 5, 8, 10]
     dataset_default = [diabetes_data]
 
-    def __init__(self, *args, **kwargs):
-        super().__init__(*args, **kwargs)
+    def __init__(
+        self,
+        metric=None,
+        sleep=0,
+        evaluate_from_data=False,
+    ):
+        super().__init__(metric, sleep, evaluate_from_data)
 
     def search_space(
         self,
@@ -69,8 +74,13 @@ class GradientBoostingRegressorFunction(MachineLearningFunction):
     cv_default = [2, 3, 4, 5, 8, 10]
     dataset_default = [diabetes_data]
 
-    def __init__(self, *args, **kwargs):
-        super().__init__(*args, **kwargs)
+    def __init__(
+        self,
+        metric=None,
+        sleep=0,
+        evaluate_from_data=False,
+    ):
+        super().__init__(metric, sleep, evaluate_from_data)
 
     def search_space(
         self,
diff --git a/src/surfaces/test_functions/mathematical/test_functions_2d/ackley_function.py b/src/surfaces/test_functions/mathematical/test_functions_2d/ackley_function.py
index e1ee317..c09bff5 100644
--- a/src/surfaces/test_functions/mathematical/test_functions_2d/ackley_function.py
+++ b/src/surfaces/test_functions/mathematical/test_functions_2d/ackley_function.py
@@ -25,7 +25,12 @@ class AckleyFunction(MathematicalFunction):
     global_minimum = r"f(\vec{x}=0) = 0"
 
     def __init__(
-        self, A=20, angle=2 * np.pi, metric="score", input_type="dictionary", sleep=0
+        self,
+        A=20,
+        angle=2 * np.pi,
+        metric="score",
+        input_type="dictionary",
+        sleep=0,
     ):
         super().__init__(metric, input_type, sleep)