In recent versions you can define functions arguments multiple ways. Here is how they can be defined and called:

Copydef fun(a, b, c='foo'):
    ...
fun(1, 2)
fun(1, 2, 'bar')
fun(1, b=2)
fun(1, b=2, c='bar')
fun(a=1, b=2, c='bar')

where a and b are positional or keyword args and c is an optional positional or keyword arg

or

Copydef fun(a, b, *, c, d='foo'):
    ...
fun(1, 2, c='bar')
fun(1, b=2, c='bar', d='baz')
fun(a=1, b=2, c='bar', d='baz')

where a and b are positional or keyword args and c is a mandatory kwarg and d is an optional kwarg

or

Copydef fun(a, b, /, c, *, d, e='foo'):
    ...
fun(1, 2, 3)
fun(1, 2, c=3)
fun(1, 2, c=3, d='bar')

where a and b are positional only args, c is a positional or keyword arg and d is a mandatory kwarg and e is an optional kwarg

Just use the *args parameter, which allows you to pass as many arguments as you want after your a,b,c. You would have to add some logic to map args->c,d,e,f but its a "way" of overloading.

Copydef myfunc(a,b, *args, **kwargs):
   for ar in args:
      print ar
myfunc(a,b,c,d,e,f)

And it will print values of c,d,e,f

Similarly you could use the kwargs argument and then you could name your parameters.

Copydef myfunc(a,b, *args, **kwargs):
      c = kwargs.get('c', None)
      d = kwargs.get('d', None)
      #etc
myfunc(a,b, c='nick', d='dog', ...)

And then kwargs would have a dictionary of all the parameters that are key valued after a,b