Fix Python – Bare asterisk in function arguments?

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, *, fix_imports=True)

I know about a single and double asterisks preceding arguments (for variable number of arguments), but this precedes nothing. And I’m pretty sure this has nothing to do with pickle….

Fix Python – Expanding tuples into arguments

Is there a way to expand a Python tuple into a function – as actual parameters?
For example, here expand() does the magic:
some_tuple = (1, “foo”, “bar”)

def myfun(number, str1, str2):
return (number * 2, str1 + str2, str2 + str1)

myfun(expand(some_tuple)) # (2, “foobar”, “barfoo”)

I know one could define myfun as myfun((a, b, c)), but of c….