$($Counting Duplicate Words$)$ Write a script that uses a dictionary to determine and

print the number of duplicate words in a sentence. Treat uppercase and lowercase letters

the same and assume there is no punctuation in the sentence. Use the techniques you

learned in Section $6\mathrm{.}2\mathrm{.}7.$ Words with counts larger than $1$ have duplicates. Hint: use the

lower$()$ method to convert all words into lower case.