Python 如何调试程序崩溃错误

# sample.py

def func(n):
 return n + 10

func('Hello')

bash % python3 -i sample.py
Traceback (most recent call last):
 File "sample.py", line 6, in <module>
 func('Hello')
 File "sample.py", line 4, in func
 return n + 10
TypeError: Can't convert 'int' object to str implicitly
>>> func(10)
20
>>>

>>> import pdb
>>> pdb.pm()
> sample.py(4)func()
-> return n + 10
(Pdb) w
 sample.py(6)<module>()
-> func('Hello')
> sample.py(4)func()
-> return n + 10
(Pdb) print n
'Hello'
(Pdb) q
>>>

import traceback
import sys

try:
 func(arg)
except:
 print('**** AN ERROR OCCURRED ****')
 traceback.print_exc(file=sys.stderr)

>>> def sample(n):
...  if n > 0:
...    sample(n-1)
...  else:
...    traceback.print_stack(file=sys.stderr)
...
>>> sample(5)
 File "<stdin>", line 1, in <module>
 File "<stdin>", line 3, in sample
 File "<stdin>", line 3, in sample
 File "<stdin>", line 3, in sample
 File "<stdin>", line 3, in sample
 File "<stdin>", line 3, in sample
 File "<stdin>", line 5, in sample
>>>

import pdb

def func(arg):
 ...
 pdb.set_trace()
 ...