Bare asterisk in function arguments?

Question

What does a bare asterisk in the arguments of a function do?

When I looked at the pickle module, I see this:

pickle.dump(obj, file, protocol=None, *,         


        

Answer 1

Suppose you have function:

def sum(a,key=5):
    return a + key 

You can call this function in 2 ways:

sum(1,2) or sum(1,key=2)

Suppose you want function sum to be called only using keyword arguments.

You add * to the function parameter list to mark the end of positional arguments.

So function defined as:

def sum(a,*,key=5):
    return a + key 

may be called only using sum(1,key=2)