如何将多个值添加到python字典中的键？

Question

M = int(input())mydict = {}for i in range (M):    j,k = map(int, input().split())    try:        mydict[j].append(k)    except KeyError :        mydict[j] = kprint(mydict)当我运行代码时：Traceback (most recent call last):  File "source_file.py", line 7, in <module>    mydict[j].append(k)AttributeError: 'int' object has no attribute 'append'