diff --git a/cvpubsubs/webcam_pub/callbacks.py b/cvpubsubs/webcam_pub/callbacks.py
index 3bc18bf..e972172 100644
--- a/cvpubsubs/webcam_pub/callbacks.py
+++ b/cvpubsubs/webcam_pub/callbacks.py
@@ -77,7 +77,9 @@ class pytorch_function_display_callback(object):  # NOSONAR
         >>> img = np.zeros((300, 300, 3))
         >>> def fun(array, coords, finished):
         ...     rgb = torch.empty(array.shape).uniform_(0,1).type(torch.DoubleTensor).to(array.device)/150.0
-        ...     array[coords] = (array[coords+np.ones_like(coords)] + rgb[coords])%1.0
+        ...     trans = np.zeros_like(coords)
+        ...     trans[0,...] = 1
+        ...     array[coords] = (array[coords+trans] + rgb[coords])%1.0
         >>> VideoHandlerThread(video_source=img, callbacks=pytorch_function_display_callback(fun)).display()
 
         thanks: https://medium.com/@awildtaber/building-a-rendering-engine-in-tensorflow-262438b2e062