My very first attempt to use the pstats browser failed
immediately.

w221:~/src/python/dist/src/Tools/compiler> python2.1
../../Lib/pstats.py compiler/__init__.py.prof 
Welcome to the profile statistics browser.
% help

Documented commands (type help <topic>):
========================================
EOF             add             callees        
callers         quit           
read            reverse         sort           
stats           strip           

Undocumented commands:
======================
help            

% callers
Traceback (most recent call last):
  File "../../Lib/pstats.py", line 646, in ?
    ProfileBrowser(initprofile).cmdloop()
  File "../../Lib/cmd.py", line 86, in cmdloop
    stop = self.onecmd(line)
  File "../../Lib/cmd.py", line 124, in onecmd
    return func(arg)
  File "../../Lib/pstats.py", line 580, in do_callers
    return self.generic('callers', line)
  File "../../Lib/pstats.py", line 563, in generic
    apply(getattr(self.stats, fn), processed)
AttributeError: Stats instance has no attribute
'callers'