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: 'an elephant is standing in the road by the truck'. Reverse all words of length '5' in the given sentence.
Example Output: an elephant is standing in the road by the kcurt

Example Input: Sentence: 'an omelet with hash browns and toast as breakfast'. Reverse all words of length '5' in the given sentence.
Example Output: an omelet with hash browns and tsaot as breakfast

Example Input: Sentence: 'a small black bear sitting on a log'. Reverse all words of length '2' in the given sentence.
Example Output:
a small black bear sitting no a log