Problem of mission Sort Array by Element Frequency

I got a problem in the following mission:

Station : Home Mission : Sort Array by Element Frequency Test case : frequency_sort([4, 6, 2, 2, 6, 4, 4, 4]) #[4, 4, 4, 4, 6, 6, 2, 2]

Problem : Your result:[4,4,4,4,6,6,2,2,2] Right result:[4,4,4,4,2,2,2,6,6] Fail:frequency_sort([4,6,2,2,2,6,4,4,4])

The "Right result" seems not right!