diff --git a/pygal/graph/dual.py b/pygal/graph/dual.py
index 9d4792a..792228a 100644
--- a/pygal/graph/dual.py
+++ b/pygal/graph/dual.py
@@ -56,7 +56,7 @@ class Dual(Graph):
         # In case of dual, x labels must adapters and so majors too
         self.x_labels_major = self.x_labels_major and list(
             map(self._x_adapt, self.x_labels_major))
-        super()._compute_x_labels_major()
+        super(Dual, self)._compute_x_labels_major()
 
     def _get_x_label(self, i):
         """Convenience function to get the x_label of a value index"""
diff --git a/pygal/graph/graph.py b/pygal/graph/graph.py
index a416148..c91b1a7 100644
--- a/pygal/graph/graph.py
+++ b/pygal/graph/graph.py
@@ -777,7 +777,7 @@ class Graph(PublicApi):
             else:
                 self._y_labels_major = [self._y_labels[
                     int(i * (label_count - 1) / (major_count - 1))][1]
-                                        for i in range(major_count)]
+                    for i in range(major_count)]
 
         elif self.y_labels_major:
             self._y_labels_major = list(map(self._adapt, self.y_labels_major))