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 computer and laptop sitting on a desk'. Reverse all words of length '6' in the given sentence.
Example Output: a computer and potpal sitting on a desk

Example Input: Sentence: 'a traffic light with road instructions directs traffic'. Reverse all words of length '4' in the given sentence.
Example Output: a traffic light htiw daor instructions directs traffic

Example Input: Sentence: 'purple ice cream sits in a styrofoam cup'. Reverse all words of length '4' in the given sentence.
Example Output:
purple ice cream stis in a styrofoam cup