Variable number of function arguments

1. Python function arguments - a reminder
2. Functions with unknown number of argumerns
3. Variable length argument list with * and **
4. Passing arguments as they were received (but incorrectly)
5. Unpacking args before passing them on
6. Exercise: implement the my_sum function
7. Solution: implement the my_sum function
8. Exercise: implement the reduce function
9. Soluton: implement the reduce function
10. Exercise: sort pairs
11. Solution: sort pairs