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.

Example Input: Sentence: 'a street pole with some signs sitting on top of it'. Reverse all words of length '6' in the given sentence.
Example Output: a teerts pole with some signs sitting on top of it

Example Input: Sentence: 'a panda bear walking around in the middle of a enclosure'. Reverse all words of length '6' in the given sentence.
Example Output: a panda bear walking dnuora in the elddim of a enclosure

Example Input: Sentence: 'a dog that is sitting on an arm rest in a car'. Reverse all words of length '7' in the given sentence.
Example Output:
a dog that is gnittis on an arm rest in a car