Index: trunk/SDToolBox/extract_data.py
===================================================================
diff -u -r109 -r110
--- trunk/SDToolBox/extract_data.py	(.../extract_data.py)	(revision 109)
+++ trunk/SDToolBox/extract_data.py	(.../extract_data.py)	(revision 110)
@@ -272,7 +272,7 @@
                 self,
                 nn_idx: Tuple[list, list]) -> Tuple[Tuple[list, list], list]:
             # Get unique indices.
-            if not isinstance(nn_idx[0], list):
+            if not isinstance(nn_idx[0], (list, np.ndarray)):
                 nn_idx = [nn_idx[0]], [nn_idx[1]]
             combined_array = np.stack(nn_idx, axis=-1)
             unique_nn, unique_idx = \