diff --git a/modules/aeolus/aeolus_amv.py b/modules/aeolus/aeolus_amv.py
index 15668565edbad97cd3fa5112914d362e29fa74b9..4b358e99872d6f0223cd71f6351a320cba98b4b9 100644
--- a/modules/aeolus/aeolus_amv.py
+++ b/modules/aeolus/aeolus_amv.py
@@ -238,7 +238,7 @@ def create_file2(filename, raob_to_amv_dct, raob_dct, amv_files):
     rootgrp.close()
 
 
-def run_best_fit_all(amv_dir, source, product_dir, product, raob_path=None, gfs_path=None, full_domain=False):
+def run_best_fit_all(amv_dir, source, product_dir, product, raob_path, gfs_path, full_domain=False):
     amv_files = get_datasource(amv_dir, 10, source)
     prd_files = get_datasource(product_dir, 10, product)
     gfs_files = get_datasource(gfs_path, 10, 'GFS')