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: 'an old fashioned bathroom with gravity fed toilet and bidet and a gas water heater on the wall'. Reverse all words of length '7' in the given sentence.

an old fashioned bathroom with ytivarg fed toilet and bidet and a gas water heater on the wall