diff --git a/python/fbprophet/diagnostics.py b/python/fbprophet/diagnostics.py
index 26c4eb0..7dab24b 100644
--- a/python/fbprophet/diagnostics.py
+++ b/python/fbprophet/diagnostics.py
@@ -111,18 +111,18 @@ def cross_validation(model, horizon, period=None, initial=None, multiprocess=Fal
     if model.uncertainty_samples:
         predict_columns.extend(['yhat_lower', 'yhat_upper'])
 
-    predicts = []
     cutoffs = generate_cutoffs(df, horizon, initial, period)
 
     if multiprocess is True:
         with Pool() as pool:
             logger.info('Running cross validation in multiprocessing mode')
-            input_df = ((df, model, cutoff, horizon, predict_columns) for cutoff in tqdm(cutoffs))
+            input_df = ((df, model, cutoff, horizon, predict_columns) for cutoff in cutoffs)
             predicts = pool.starmap(single_cutoff_forecast, input_df)
     else:
-        if multiprocess is False:
-            for cutoff in tqdm(cutoffs):
-                predicts.append(single_cutoff_forecast(df, model, cutoff, horizon, predict_columns))
+        predicts = [
+            single_cutoff_forecast(df, model, cutoff, horizon, predict_columns)
+            for cutoff in tqdm(cutoffs)
+        ]
 
     # Combine all predicted pd.DataFrame into one pd.DataFrame
     return pd.concat(predicts, axis=0).reset_index(drop=True)