diff --git a/scripts/build_ammonia_production.py b/scripts/build_ammonia_production.py
index bfcfaf02..77b33075 100644
--- a/scripts/build_ammonia_production.py
+++ b/scripts/build_ammonia_production.py
@@ -7,8 +7,8 @@ Build historical annual ammonia production per country in ktonNH3/a.
 """
 
 import country_converter as coco
-import pandas as pd
 import numpy as np
+import pandas as pd
 
 cc = coco.CountryConverter()
 
@@ -33,9 +33,7 @@ if __name__ == "__main__":
     years = [str(i) for i in range(2013, 2018)]
 
     ammonia = ammonia[years]
-    ammonia.replace("--",
-                    np.nan,
-                    inplace=True)
+    ammonia.replace("--", np.nan, inplace=True)
     ammonia = ammonia.astype(float)
 
     # convert from ktonN to ktonNH3