[Python] How to debug the stack trace that causes a subsequent exception in python?

Python (and ipython) has very powerful post-mortem debugging capabilities, allowing variable inspection and command execution at each scope in the traceback. The up/down debugger commands allow changing frame for the stack trace of the final exception, but what about the __cause__ of that exception, as defined by the raise ... from ... syntax?

Python 3.7.6 (default, Jan 8 2020, 13:42:34)
Type 'copyright', 'credits' or 'license' for more information
IPython 7.11.1 -- An enhanced Interactive Python. Type '?' for help.

In [1]: def foo():
...: bab = 42
...: raise TypeError
...:

In [2]: try:
...: foo()
...: except TypeError as err:
...: barz = 5
...: raise ValueError from err
...:
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-2-dd046d7cece0> in <module>
1 try:
----> 2 foo()
3 except TypeError as err:

<ipython-input-1-da9a05838c59> in foo()
2 bab = 42
----> 3 raise TypeError
4

TypeError:

The above exception was the direct cause of the following exception:

ValueError Traceback (most recent call last)
<ipython-input-2-dd046d7cece0> in <module>
3 except TypeError as err:
4 barz = 5
----> 5 raise ValueError from err
6

ValueError:

In [3]: %debug
> <ipython-input-2-dd046d7cece0>(5)<module>()
2 foo()
3 except TypeError as err:
4 barz = 5
----> 5 raise ValueError from err
6

ipdb> barz
5
ipdb> bab
*** NameError: name 'bab' is not defined
ipdb> down
*** Newest frame
ipdb> up
*** Oldest frame


Is there a way to access bab from the debugger?

EDIT: I realized post-mortem debugging isn't just a feature of ipython and ipdb, it's actually part of vanilla pdb. The above can also be reproduced by putting the code into a script testerr.py and running python -m pdb testerr.py and running continue. After the error, it says

Uncaught exception. Entering post mortem debugging
Running 'cont' or 'step' will restart the program


and gives a debugger at the same spot.

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