from datetime import timedelta
from random import randint

from dateutil.relativedelta import relativedelta


def date_range(start_date, end_date):
    for n in range(int((end_date - start_date).days)):
        yield start_date + timedelta(n)


def random_datetime(start_datetime, end_datetime):
    return start_datetime + timedelta(
        seconds=randint(0, int((end_datetime - start_datetime).total_seconds())))


def get_last_months(start_datetime, num):
    months = set()
    for i in range(num):
        month = start_datetime - relativedelta(months=i)
        months.add(month.date().strftime('%Y%m'))
    return months