python---提取列表里的字典，在生成一个字典

mlist = [{'sid':'501','7月': 9000,'8月':9500,'9月':9200},
             {'sid':'502','7月': 8000,'8月':8500,'9月':8200},
             {'sid':'503','7月': 7000,'8月':7500,'9月':7200}]

res_dict = {}   # 存放结果字典
res_list = []   # 存放结果列表
index_key = ""
for it in mlist:
    for chi in it.keys():
        if chi!="sid":
            res_list.append(it[chi])
        else:
            index_key = it[chi]
    res_dict[index_key] = res_list
    res_list = []

print(res_dict)