Write function remove_duplicate_words(sentence) which takes an input parameter sentence (type string), and returns a string that has all duplicated words removed from sentence.

The words in the returned string should be sorted in alphabetical order.

For example:

Test	Result
simple_sentence = remove_duplicate_words("hello hello hello hello hello") print(simple_sentence)	hello
simple_sentence = remove_duplicate_words("hello hello hi hi hello hi hello hi hi bye") print(simple_sentence)	bye hello hi