In this task, you need to remove 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.

Sentence: 'a picture hanging on the wall being reflected in a mirror that hangs over a bathroom sink'. Remove all words of length '8' in the given sentence.
a picture hanging on the wall being reflected in a mirror that hangs over a sink