Write a function in PYTHON called save$\_$rand$\_$num, which takes two parameters: upper$\_$bound and how$\_$many with default value $100$ and $20,$ that is$,$ if you call the function without passing arguments, the default values $100$ and $20$ will be used: generate $20$ random numbers within the range $1.\mathrm{.}100.$

The function saves each number generated in a output file called rand$\_$data.txt