put the extra line of history in a try-except, attribute might not exist

da/analysis/expand_mixingratios.py

@@ -89,7 +89,10 @@ def WriteMixingRatios(DaCycle):
      
 
             ncf_out.Caution  = '==================================================================================='
-            ncf_out.History += '\nOriginal observation file modified by user %s on %s\n' % (os.environ['USER'], datetime.today().strftime('%F'),)
+            try:
+                ncf_out.History += '\nOriginal observation file modified by user %s on %s\n' % (os.environ['USER'], datetime.today().strftime('%F'),)
+            except:
+                ncf_out.History = '\nOriginal observation file modified by user %s on %s\n' % (os.environ['USER'], datetime.today().strftime('%F'),)
             ncf_out.CTDAS_info = 'Simulated values added from a CTDAS run by %s on %s\n' % (os.environ['USER'], datetime.today().strftime('%F'),)\
                                + '\nCTDAS was run on platform %s' % (os.environ['HOST'],)\
                                + '\nCTDAS job directory was %s' % (DaCycle['dir.da_run'],)\