diff --git a/src/extraction/core/functions/distributors.py b/src/extraction/core/functions/distributors.py
index 40e8fff96b4da6fe417a7ead89d9eb6b54993137..786429c1cc294c324340f66c3a70b2d74a57b1df 100644
--- a/src/extraction/core/functions/distributors.py
+++ b/src/extraction/core/functions/distributors.py
@@ -13,7 +13,7 @@ def trap_apply(cell_fun, cell_masks, *args, **kwargs):
     cell_fun: function
         Function to apply to the cell (from extraction/cell.py)
     cell_masks: 3d array
-        Segmentation masks for the cells
+        Segmentation masks for the cells. Note that cells are the last dimension N (Y,X,N)
     *args: tuple
         Trap_image and any other arguments to pass if needed to custom functions.
     **kwargs: dict