diff --git a/3_visualize/src/python_scripts/plot_utils.py b/3_visualize/src/python_scripts/plot_utils.py
new file mode 100644
index 00000000..13222e93
--- /dev/null
+++ b/3_visualize/src/python_scripts/plot_utils.py
@@ -0,0 +1,22 @@
+import matplotlib.pyplot as plt
+validation_sites = ["01472104", "01473500", "01481500"]
+test_sites = ["01475530", "01475548"]
+
+model_order = ["0_baseline_LSTM", "1a_multitask_do_gpp_er",
+               "1_metab_multitask", "2_multitask_dense"]
+
+def mark_val_sites(ax):
+    labels = [item.get_text() for item in ax.get_xticklabels()]
+    new_labels = []
+    for l in labels:
+        if l in validation_sites:
+            new_labels.append("*" + l)
+        else:
+            new_labels.append(l)
+
+    ax.set_xticklabels(new_labels)
+
+    fig = plt.gcf()    
+    fig.text(0.5, 0, "* validation site")
+
+    return ax