How to use the contextlib2.redirect_stderr function in contextlib2

def do_help(self, arglist):
        """List available commands with "help" or detailed help with "help cmd"."""
        if arglist:
            # Getting help for a specific command
            funcname = self._func_named(arglist[0])
            if funcname:
                # Check to see if this function was decorated with an argparse ArgumentParser
                func = getattr(self, funcname)
                if func.__dict__.get('has_parser', False):
                    # Function has an argparser, so get help based on all the arguments in case there are sub-commands
                    new_arglist = arglist[1:]
                    new_arglist.append('-h')

                    # Temporarily redirect all argparse output to both sys.stdout and sys.stderr to self.stdout
                    with redirect_stdout(self.stdout):
                        with redirect_stderr(self.stdout):
                            func(new_arglist)
                else:
                    # No special behavior needed, delegate to cmd base class do_help()
                    cmd.Cmd.do_help(self, funcname[3:])
        else:
            # Show a menu of what commands help can be gotten for
            self._help_menu()