removes int_to_slice and moves logic inline

zarr/indexing.py

@@ -829,18 +829,14 @@ def pop_fields(selection):
     return fields, selection
 
 
-def int_to_slice(dim_selection):
-    return slice(dim_selection, dim_selection + 1, 1)
-
-
 def make_slice_selection(selection):
     ls = []
     for dim_selection in selection:
         if is_integer(dim_selection):
-            ls.append(int_to_slice(dim_selection))
+            ls.append(slice(dim_selection, dim_selection + 1, 1))
         elif isinstance(dim_selection, np.ndarray):
             if len(dim_selection) == 1:
-                ls.append(int_to_slice(dim_selection[0]))
+                ls.append(slice(dim_selection[0], dim_selection[0] + 1, 1))
             else:
                 raise ArrayIndexError()
         else: