diff --git a/random_survival_forest/RandomSurvivalForest.py b/random_survival_forest/RandomSurvivalForest.py
index b019682..ad2c7ed 100644
--- a/random_survival_forest/RandomSurvivalForest.py
+++ b/random_survival_forest/RandomSurvivalForest.py
@@ -59,6 +59,8 @@ def fit(self, x, y):
     def create_tree(self, x, y, i):
         """
         Grows a survival tree for the bootstrap samples.
+        :param y: label data frame y with survival time as the first column and event as second
+        :param x: feature data frame x
         :param i: Indices
         :return: SurvivalTree
         """
diff --git a/random_survival_forest/splitting.py b/random_survival_forest/splitting.py
index b8dfe87..6d4d3ea 100644
--- a/random_survival_forest/splitting.py
+++ b/random_survival_forest/splitting.py
@@ -58,12 +58,12 @@ def logrank_statistics(x, y, feature, min_leaf):
         feature2 = list(x_feature[x_feature > split_val].index)
         if len(feature1) < min_leaf or len(feature2) < min_leaf:
             continue
-        durations_A = y.iloc[feature1, 0]
-        event_observed_A = y.iloc[feature1, 1]
-        durations_B = y.iloc[feature2, 0]
-        event_observed_B = y.iloc[feature2, 1]
-        results = logrank_test(durations_A=durations_A, durations_B=durations_B,
-                               event_observed_A=event_observed_A, event_observed_B=event_observed_B)
+        durations_a = y.iloc[feature1, 0]
+        event_observed_a = y.iloc[feature1, 1]
+        durations_b = y.iloc[feature2, 0]
+        event_observed_b = y.iloc[feature2, 1]
+        results = logrank_test(durations_A=durations_a, durations_B=durations_b,
+                               event_observed_A=event_observed_a, event_observed_B=event_observed_b)
         score = results.test_statistic
 
         if score > score_opt: