严格传入函数的参数类型，并自定义抛出异常
执行结果：
33
44
99
Traceback (most recent call last):
File "functions.py", line 34, in <module>
print res2(44, "55")
File "functions.py", line 8, in sum
raise "Parameter type error, two parameter types must be integer"
TypeError: exceptions must be old-style classes or derived from BaseException, not str