 printGrade((101, "A"))
 printGrade((55, "E"))
 printGrade((94, "A"))
+/*:
+Above we validate the grade number and grade letter using a `guard` statement and only executing the correct print statement if the grade number and grade letter are in the correct range.
+*/
 /*:
 ## Error Handling
 

        
        throw GradeError.BadLetter(youPassed: passed, shouldBe: shouldBe)
    }
    
}

let myGrade = try createMyGrade(93, letter: "A")
/*:
**Exercise:**
>> **Example Output:**
* HERE
>> **Constraints:**
* HERE
*/
/*:
**Checkpoint:**
At this point, ...
*/
/*:
**Keywords to remember:**
- `func` =
- `inout` =
- `return` =
- `guard` =
- `do` =
- `try` =
- `throw` =
- `throws` =
- `catch` =
- `defer` =
*/
/*:
**Supporting Chapters:**
- [Functions](https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Functions.html)
- [Error Handling](https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/ErrorHandling.html)
*/
/*:

    print("You passed in a bad number")
}
/*:
Above ...
*/
/*:
## Clean up after yourself

*/
func createMyGrade(number: Int, letter: String) throws -> (Int, String)? {
