def get_month_n_days_from_cumulative(monthly_cumulative_days):
    """
    Transform consecutive number of days in monthly data to actual number of days.

    EnergyPlus monthly results report a total consecutive number of days for each day.
    Raw data reports table as 31, 59..., this function calculates and returns
    actual number of days for each month 31, 28...
    """
    old_num = monthly_cumulative_days.pop(0)
    m_actual_days = [old_num]
    for num in monthly_cumulative_days:
        new_num = num - old_num
        m_actual_days.append(new_num)
        old_num += new_num
    return m_actual_days