Create a function that returns a number, based on the string provided. Here is a list of all digits:
| String | Number |
|---|---|
| "one" | 1 |
| "two" | 2 |
| "three" | 3 |
| "four" | 4 |
| "five" | 5 |
| "six" | 6 |
| "seven" | 7 |
| "eight" | 8 |
| "nine" | 9 |
| "zero" | 0 |
word("one") ➞ 1
word("two") ➞ 2
word("nine") ➞ 9
All numbers will be single digit positive integers.