Definition: In this task, you need to reverse all words of a given length in the sentence. The number of letters in a word determine its length. For example, the length of the word "apple" is 5.
Input: Sentence: 'two birthday cakes with lit candles sitting in front of cases of beer'. Reverse all words of length '4' in the given sentence.

two birthday cakes htiw lit candles sitting in front of cases of reeb