如何获取上一年的当月和前几个月

import datetime

# 获取当前日期和时间
now = datetime.datetime.now()

# 计算上一年的年份
last_year = now.year - 1

# 获取上一年的当月
last_month = datetime.datetime(last_year, now.month, 1).strftime("%Y-%m")

# 获取前几个月
num_of_months = 3
previous_months = []
for i in range(num_of_months):
    month = now.month - i - 1
    year = now.year
    if month <= 0:
        month += 12
        year -= 1
    previous_month = datetime.datetime(year, month, 1).strftime("%Y-%m")
    previous_months.append(previous_month)

print("上一年的当月：", last_month)
print("前几个月：", previous_months)