median of an array

arr = [2.4, 5.1, 6.7, 8.9]

arr.sort()

if len(arr)%2 == 0:
    res = (arr[round(len(arr)/2) - 1] + arr[round(len(arr)/2)])/2
else:
    res = arr[int(len(arr)/2)]
    
print(res)