public IEnumerable <TKey> JoinKeysTest <TKey, TElement>(IEnumerable <Dictionary <TKey, TElement> > source)
{
IEnumerable <TKey> result = EnumerableExtension.JoinKeys <TKey, TElement>(source);
return(result);
// TODO: add assertions to method EnumerableExtensionTest.JoinKeysTest(IEnumerable`1<Dictionary`2<!!0,!!1>>)
}