写了一个demo异常类，没有继承BaseException类，提示报如下错误，很明显只要继承一下BaseException就可以了。
TypeError: catching classes that do not inherit from BaseException is not allowed 捕获到一个没有继承BaseException的异常类（这是不被允许的）。
Exception ignored in: <generator object demo_exc_handling at 0x000001D06C66E200>
Traceback (most recent call last):
File "a5_3_coroutine_exception.py", line 10, in demo_exc_handling
TypeError: catching classes that do not inherit from BaseException is not allowed
class DemoException(): # DemoException(BaseException) 为正确写法
"""demo异常类型"""
pass
def demo_exc_handling():
print('-> coroutine started')
while True:
try:
var = yield
except DemoException as e:
print('*** DemoException handled. Continuing...')
else:
print('-> coroutine received: {!r}'.format(var))
# raise RuntimeError('This line should never run.')
cor_exc = demo_exc_handling()
cor_exc.send(None)
cor_exc.send(1)
