diff --git a/src/energy_data_project/T08_WorldCities.py b/src/energy_data_project/T08_WorldCities.py
index 6c94534..08f34aa 100644
--- a/src/energy_data_project/T08_WorldCities.py
+++ b/src/energy_data_project/T08_WorldCities.py
@@ -13,7 +13,8 @@ def get_population_of_country(df, country):
     :raises: KeyError if column is missing
     """
     cities = df[df["country"] == country]
-    return cities["population"].sum()
+    pop = cities["population"].sum()
+    return pop
 
 def get_cities_beyond_latitude(df, lat, north=True):
     """