Exception trapping
Exception types ：
SystemExit ： The interpreter requests exit
Keyboardinterrupt： User interrupt execution
GeneratorExit： generator （generator） An exception occurs to notify the exit
Exception： Base class of generic type
```
try:
pass
# Code that may go wrong
except:
pass
# at that time try When there is an error in the code execution , Will execute exept The code in , You can handle exceptions here
else:
pass
#try There are no errors in the code execution in , Will perform else The code in
finally:
pass
#try No matter what goes wrong ,finally All the code in
```
```
try:
pass
# Code that could go wrong
except Exception types as e:
pass
```
assert Assertion ：
assert Expected results == The actual result
raise： Actively throw an exception
