diff --git a/system/dataset.py b/system/dataset.py
index ec49afe..a9d0d31 100644
--- a/system/dataset.py
+++ b/system/dataset.py
@@ -151,6 +151,8 @@ class Dataset:
         Identifiers are the unique names (strings) for a variable in a given dim.
         Index (Indices) are the Identifiers position in a matrix in a given dim.
         """
+        if len(indices)==0:
+            indices=[]
         if sorted==True:
             items = self._map[dim].items()
             backitems = [ [v[1],v[0]] for v in items]