The problem of chapter B5.1

[MaxforCherubim]

The code is wrong.

from IPython.core.debugger import Pdb

def set_trace():
    Pdb(.set_trace(sys._getframe().f_back)

def debug(f, *args, **kwargs):
    pdb = Pdb()
    return pdb.runcall(f, *args, **kwargs)

It should be

from IPython.core.debugger import Pdb
import sys

def set_trace():
        Pdb.set_trace(sys._getframe().f_back)

def debug(f, *arg, **kwargs):
        pdb = Pdb()
        return pdb.runcall(f, *args, **kwargs)

But even the code get repaired, there still exist a AttributeError
AttributeError: 'frame' object has no attribute 'initial_frame'