[Python] sys._getframe に渡す depth

>>> import sys
>>> for i in range(-1, 100):
	print '%d: %s' % (i, sys._getframe(i).f_code.co_filename, )

	
-1: <pyshell#2>
0: <pyshell#2>
1: C:\Python25\lib\idlelib\run.py
2: C:\Python25\lib\idlelib\run.py
3: <string>

Traceback (most recent call last):
  File "<pyshell#2>", line 2, in <module>
    print '%d: %s' % (i, sys._getframe(i).f_code.co_filename, )
ValueError: call stack is not deep enough