find missing ranges between low and high in the given array ex 3 5 lo1 hi10 answer 1 2 4 4 6 10 after done iterating thru array append remainder to list
def missing_ranges(arr, lo, hi):

    res = []
    start = lo

    for n in arr:

        if n == start:
            start += 1
        elif n > start:
            res.append((start, n-1))
            start = n + 1

    if start <= hi:                 
        res.append((start, hi))     

    return res