TASK 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.
PROBLEM: Sentence: 'a couple walking in the rain using and umbrella'. Reverse all words of length '6' in the given sentence.

SOLUTION: a elpuoc walking in the rain using and umbrella

PROBLEM: Sentence: 'a person is on the court and playing tennis'. Reverse all words of length '3' in the given sentence.

SOLUTION: a person is on eht court dna playing tennis

PROBLEM: Sentence: 'a bear walking on the mountain side sniffing the plants'. Reverse all words of length '7' in the given sentence.

SOLUTION:
a bear gniklaw on the mountain side sniffing the plants