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.

Sentence: 'a person wearing a black jacket is standing next to a horse'. Reverse all words of length '8' in the given sentence.
a person wearing a black jacket is gnidnats next to a horse

Sentence: 'a donut sitting in front of a laptop with black and orange sprinkles'. Reverse all words of length '1' in the given sentence.
a donut sitting in front of a laptop with black and orange sprinkles

Sentence: 'a couple of boys that are sitting down behind a glass'. Reverse all words of length '7' in the given sentence.

a couple of boys that are gnittis down behind a glass