Goal: Learn to use positional and keyword parameters with defaults.

Assignment: Write a function named evaluate$\_$g rade that determines whether a student has passed or failed an exam. The function should have three parameters:

$-$ name $($positional$-$only$)$: The name of the student.

$-$ score $($positional$-$only$)$: The student's score on the exam. Assume this will always be an integer in the range of $0$ through $100.$

$-$ passing$\_$score $($keyword$-$only, with the default value $50)$: The minimum score required to pass the exam.

If the student's score is greater$-$than or equal$-$to passing$\_$score, the function should print the message $"$ passed the exam. $",$ where is the value of the name parameter. Otherwise, it should print the message $"$ failed the exam.".