remove UA from countries list for synthetic load data

scripts/build_electricity_demand.py

@@ -311,6 +311,8 @@ if __name__ == "__main__":
         logger.info("Supplement missing data with synthetic data.")
         fn = snakemake.input.synthetic
         synthetic_load = pd.read_csv(fn, index_col=0, parse_dates=True)
+        # "UA" does not appear in synthetic load data
+        countries = list(set(countries) - set(["UA"]))
         synthetic_load = synthetic_load.loc[snapshots, countries]
         load = load.combine_first(synthetic_load)