def divide_list(list, perc=0.5):
    """
    Divide a list into two new lists. perc is the first list's share. If perc=0.6 then the first new list will have 60 percent of the original list.
    example : f,s = divide_list([1,2,3,4,5,6,7], perc=0.7)
    """
    origLen = len(list)
    lim = int(perc*origLen)
    firstList = list[:lim]
    secondList = list[lim:]
    return firstList, secondList