diff --git a/tsmark/video_annotator.py b/tsmark/video_annotator.py
index c803cb2..8938a04 100755
--- a/tsmark/video_annotator.py
+++ b/tsmark/video_annotator.py
@@ -434,7 +434,17 @@ class Marker:
                 )
                 return value
 
-        return {"x0": None, "y0": None, "x1": None, "y1": None, "cx": None, "cy": None, "visible": 0, "type": None, "age": None}
+        return {
+            "x0": None,
+            "y0": None,
+            "x1": None,
+            "y1": None,
+            "cx": None,
+            "cy": None,
+            "visible": 0,
+            "type": None,
+            "age": None,
+        }
 
     def modify_point(self, position, x, y):
         """position:  tl topleft, br bottomright, c center"""
@@ -615,7 +625,7 @@ class World:
         if self.plugin:
             self.plugin(self)
 
-    def interpolate_points(self, point_index = None):
+    def interpolate_points(self, point_index=None):
         """types:
         key:  user clicked / accepted frame
         interp: interpolated frame
@@ -627,7 +637,7 @@ class World:
             point_index = self.point_index
 
         def i_point(x0=None, y0=None, x1=None, y1=None, t=None, visible=None, age=None):
-            return {"x0": x0, "y0": y0, "x1": x1, "y1": y1, "type": t, "visible": visible, "age"=age}
+            return {"x0": x0, "y0": y0, "x1": x1, "y1": y1, "type": t, "visible": visible, "age": age}
 
         def point2array(p):
 
@@ -688,7 +698,7 @@ class World:
             # clicked points (not necessary, could determine at draw time!)
             for key in point_keys:
                 self.points_interpolated[point_index][key]["type"] = "key"
-            age=0
+            age = 0
             for key in self.points_interpolated[point_index]:
                 if self.points_interpolated[point_index][key]["type"] == "key":
                     age = 0
@@ -881,7 +891,7 @@ class World:
                 keys = list(self.points.keys())
                 for index in keys:
                     # Remove empty dicts
-                    if len(self.points[index])==0:
+                    if len(self.points[index]) == 0:
                         del self.points[index]
                         continue
                     self.point_index = index