def where(ol, value):
    """
        ol = [0, 4, 6, 8, 10, 14]
        where(ol,-1)
        where(ol,1)
        where(ol,2)
        where(ol,3)
        where(ol,4)
        where(ol,9)
        where(ol,14)
        where(ol,17)
    """
    si = None
    ei = None
    for i in range(0, ol.__len__()):
        ele = ol[i]
        if value > ele:
            si = i
        elif value == ele:
            return i, i
        else:
            ei = i
            return si, ei
    return si, ei
