sem4_2

import collections


def flatit(obj):
    mas = []
    if (isinstance(obj, str) and (len(obj) == 1)):
        mas.append(obj)
    elif (isinstance(obj, collections.Iterable)):
        for i in obj:
            mas += flatit(i)
    else:
        mas.append(obj)
    for j in mas:
        yield j