SCALES = ["o", "Ko", "Mo", "Go", "To", "Po"]


def parse_size(size):
    size, scale = size.split(maxsplit=1)
    return SCALES.index(scale), size


rows_from_sqlite = [
    ("sister_nancy.mp3", "2 Mo"),
    ("sister_nancy.mp4", "600 Mo"),
    ("titles.txt", "7 Ko"),
    ("backup.tar.bz2", "4 Go"),
]

for row in sorted(rows_from_sqlite, key=lambda row: parse_size(row[1])):
    print(row)