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: 'a motor cycle rider riding on a street with bikes parked on either sides'. Reverse all words of length '4' in the given sentence.

a motor cycle rider riding on a street htiw bikes parked on either sides