如果值匹配，如何在字典中调用键？

Question

我有这个名称及其工作的例子字典

my_dict = {'al': 'sales', 'tony': 'engineer': 'fred': 'support'}

如果作业标题（值）在if语句中匹配，我想打印字典中条目的名称（键）。

job = input("what is the job?: ")

if job in my_dict.values():

   "print the key that has that job as a value"

怎么做？