assume 0 for countries with missing data

scripts/build_industry_demand.py

@@ -210,12 +210,10 @@ def match_technology(df):
             "production[ktons/a]"
         ]
 
-        # Check for duplicate entries per country
-        duplicates = AL_prod_tom.index[AL_prod_tom.index.duplicated(keep=False)].unique()
-        if len(duplicates) > 0:
-            raise ValueError(
-            f"There are more than one entry for aluminium production data for the following countries: {', '.join(duplicates)} in 'data/AL_production.csv'"
-        )
+        # Check if aluminum data is missing for any countries
+        for country in countries_geo:
+            if country not in AL_prod_tom.index:
+                _logger.warning(f"No aluminum production data found for {country}. Filled with 0.0.")
 
         # Reindex and fill missing values with 0.0
         AL_prod_tom = AL_prod_tom.reindex(countries_geo, fill_value=0.0)