starting CountriesMergerTest

src/CountriesMerger.py

@@ -0,0 +1,10 @@
+import pandas as pd
+
+
+class CountriesMerger:
+
+    @staticmethod
+    def mergeCountriesSerieses(countriesSeriesA, countriesSeriesB):
+        return (pd
+                .merge(countriesSeriesA, countriesSeriesB, how='left', left_index=True, right_index=True)
+                .apply(lambda countries: sorted(set(countries.dropna())), axis='columns'))