Fix bug in prepare_ideal_namelist.py

templates/real-from-ideal/prepare_ideal_namelist.py

@@ -119,6 +119,8 @@ def main():
 
     # Read custom namelist parameters from configuration file
     atmosphere_custom_namelist = read_namelist(atmosphere_namelist_string)
+    # Convert output_nml to a co-group.
+    atmosphere_namelist.create_cogroup("output_nml")
 
     if atmosphere_custom_namelist is not None:
         try: