zero or one argument

[gruntfutuk]

Not to forget the keyword variant:

def something(**kwargs):
    if kwargs:
        for key, value in kwargs.items():
            print(f'{key} is {value}')
    else:
        print('nothing to see here')
            

something()
something(name="fred")
something(place="London", wetness="raining heavily", temp=10)

Which outputs:

nothing to see here
name is fred
place is London
wetness is raining heavily
temp is 10

You don't have to use *args and **kwargs, it is just convention: *mice and **cats, for example, would work. You can use *args and **kwargs in the same call.