[ Python 常見問題 ] How to enter PDB on a specific stack frame

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Question
I've written a function to enter PDB when an exception is raised (let's call it trace_on_error). Right now when I call pdb.set_trace(), pdb reasonably enters into the stack frame of trace_on_error, requiring me to have to type the up command before being able to look at the frame of the calling function.

I am trying to make trace_on_error not require users to know how its implemented to use, and thus i would like to have pdb enter into the callers stack frame. As I looked for documentation, i was hoping to find something similar to pdb.set_trace(frame_up=1), but I have not found anything.

Example Code:

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1. def trace_on_error(f, errors):  
2.     try:  
3.         return f()  
4.     except errors as e:  
5.         pdb.set_trace()  

How-To
This should do the trick (I've tested it but not sure it works in every possible case):

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1. def trace_on_error(f, errors):  
2.     try:  
3.         return f()  
4.     except errors as e:  
5.         import sys  
6.         from pdb import Pdb  
7.         Pdb().set_trace(sys._getframe().f_back)  

For sys._getframe([depth])

Return a frame object from the call stack. If optional integer depth is given, return the frame object that many calls below the top of the stack. If that is deeper than the call stack, ValueError is raised. The default for depth is zero, returning the frame at the top of the call stack.

Supplement
* Python standard library: inspect — Inspect live objects