diff --git a/y2017/control_loops/python/column.py b/y2017/control_loops/python/column.py
index 70cd649..7c34ee6 100755
--- a/y2017/control_loops/python/column.py
+++ b/y2017/control_loops/python/column.py
@@ -273,7 +273,7 @@
         profile.SetGoal(goal[2, 0])
 
         U_last = numpy.matrix(numpy.zeros((2, 1)))
-        for i in xrange(iterations):
+        for i in range(iterations):
             observer_column.Y = column.Y
             observer_column.CorrectObserver(U_last)
 
diff --git a/y2017/control_loops/python/hood.py b/y2017/control_loops/python/hood.py
index 58bd15e..7f875c9 100755
--- a/y2017/control_loops/python/hood.py
+++ b/y2017/control_loops/python/hood.py
@@ -230,7 +230,7 @@
         profile.SetGoal(goal[0, 0])
 
         U_last = numpy.matrix(numpy.zeros((1, 1)))
-        for i in xrange(iterations):
+        for i in range(iterations):
             observer_hood.Y = hood.Y
             observer_hood.CorrectObserver(U_last)
 
diff --git a/y2017/control_loops/python/indexer.py b/y2017/control_loops/python/indexer.py
index 53b856c..0c5cb6b 100755
--- a/y2017/control_loops/python/indexer.py
+++ b/y2017/control_loops/python/indexer.py
@@ -215,7 +215,7 @@
     else:
       initial_t = 0
 
-    for i in xrange(iterations):
+    for i in range(iterations):
       X_hat = indexer.X
 
       if observer_indexer is not None:
diff --git a/y2017/control_loops/python/shooter.py b/y2017/control_loops/python/shooter.py
index a825ff0..69f0af4 100755
--- a/y2017/control_loops/python/shooter.py
+++ b/y2017/control_loops/python/shooter.py
@@ -285,7 +285,7 @@
             initial_t = 0
 
         last_U = numpy.matrix([[0.0]])
-        for i in xrange(iterations):
+        for i in range(iterations):
             X_hat = shooter.X
 
             if observer_shooter is not None:
diff --git a/y2017/control_loops/python/turret.py b/y2017/control_loops/python/turret.py
index e8829eb..c5e4269 100755
--- a/y2017/control_loops/python/turret.py
+++ b/y2017/control_loops/python/turret.py
@@ -201,7 +201,7 @@
     profile.SetGoal(goal[0, 0])
 
     U_last = numpy.matrix(numpy.zeros((1, 1)))
-    for i in xrange(iterations):
+    for i in range(iterations):
       observer_turret.Y = turret.Y
       observer_turret.CorrectObserver(U_last)