Functions Exercise $1$ in Python

Problem

Write a function called avg that takes two parameters. Return the average of these two parameters. If the parameters are not numbers, return the string, Please use two numbers as parameters.

Expected Output

If the function call is avg$(10,25),$ then the function would return $17\mathrm{.}5$

If the function call is avg$(10,$ "cat"$),$ then the function would return Please use two numbers as parameters