Python - Wrong number of arguments exception?

Question

So I have a function like:

def my_code(arg1, *args):
    ....

And I want this function to only be able to take either 2 or 3 arguments (that means *args can only be 1 or 2 arguments). How do I throw an error message if the number of arguments is wrong? If I use a try/exception, is there a specific exception type for this?

Answer 1

You can get the length of args with len as you would for any tuple.

def my_code(arg1, *args):
    if not 0 < len(args) < 3:
        raise TypeError('my_code() takes either 2 or 3 arguments ({} given)'
                        .format(len(args) + 1))

my_code(1) # TypeError: my_code() takes either 2 or 3 arguments (1 given)
my_code(1, 2) # pass
my_code(1, 2, 3) # pass
my_code(1, 2, 3, 4) # TypeError: my_code() takes either 2 or 3 arguments (4 given)