adding MultiIndexExploderTest

src/Utils.py

@@ -4,3 +4,7 @@ def fillLsts(lsts, desiredLen, fillValue):
 
 def fillLst(lst, desiredLen, fillValue):
     return lst + [fillValue] * (max(desiredLen - len(lst), 0))
+
+
+def flatten(tuples):
+    return [item for tuple in tuples for item in tuple]