def begin_rate(row):
    begin_work_date = row.begin_work_date
    end_date = row.end_date
    #print(begin_work_date, end_date, type(begin_work_date))
    buf_date = (end_date - relativedelta(months=1)).replace(day=20, hour=0, minute=0, second=0)
    delta = end_date - buf_date
    if begin_work_date > buf_date:
        result_code = 0
    else:
        buf_date -= relativedelta(months=1)
        delta = end_date - buf_date
        if begin_work_date > buf_date:
            result_code = 0.5
        else:
            result_code = 1
    print('code: %s end_date = %s begin_work_date = %s delta = %s days'
          % (result_code, end_date.date(), begin_work_date.date(), delta.days))
    return result_code

deals_raw['begin_rate'] = deals_raw.apply(begin_rate, axis=1)
deals_raw.head()