diff --git a/sim_utilities.py b/sim_utilities.py
index 60c8375e19629c47558ed0c1a956ac4e9b5f2549..52cf9c005949ef18482d9ad124dedb19bd6a48f3 100644
--- a/sim_utilities.py
+++ b/sim_utilities.py
@@ -371,7 +371,7 @@ def read_conc_data(in_path, symbol_marker_color_dict, figure_range_dict):
         if symbol not in dict_concs_mean.keys():
             dict_concs_mean[symbol] = [0] * len(z_positions)
         for z, concs in enumerate(concs_list):
-            indexes = sim_utilities.range_list_to_indexes(profile_mean_range, range(len(concs)))
+            indexes = range_list_to_indexes(profile_mean_range, range(len(concs)))
             array_mask = [True] * len(concs)
             for i, _ in enumerate(concs):
                 if i in indexes: