Determine actually given command line arguments

[Henry Leyh]

Hello,
I am writing a program that gets its parameters from a combination of 
config file (using configparser) and command line arguments (using 
argparse).  Now I would also like the program to be able to _write_ a 
configparser config file that contains only the parameters actually 
given on the commandline.  Is there a simple way to determine which 
command line arguments were actually given on the commandline, i.e. does 
argparse.ArgumentParser() know which of its namespace members were 
actually hit during parse_args().

I have tried giving the arguments default values and then looking for 
those having a non-default value but this is really awkward, especially 
if it comes to non-string arguments.  Also, parsing sys.argv looks 
clumsy because you have to keep track of short and long options with and 
without argument etc. i.e. all things that I got argparse for in the 
first place.

Thanks && Greetings,
Henry