Create a function that takes a number as an argument and returns a grade based on that number.
| Score | Grade |
|---|---|
| Anything greater than 1 or less than 0.6 | "F" |
| 0.9 or greater | "A" |
| 0.8 or greater | "B" |
| 0.7 or greater | "C" |
| 0.6 or greater | "D" |
Examples:
grader(0) should be "F"
grader(1.1) should be "F"
grader(0.9) should be "A"
grader(0.8) should be "B"
grader(0.7) should be "C"
grader(0.6) should be "D"