Create a function that takes a string and returns the sum of vowels, where some vowels are considered numbers.
| Vowel | Number |
|---|---|
| A | 4 |
| E | 3 |
| I | 1 |
| O | 0 |
| U | 0 |
sum_of_vowels("Let\'s test this function.") ➞ 8
sum_of_vowels("Do I get the correct output?") ➞ 10
sum_of_vowels("I love innokodakademija!") ➞ 12
Vowels are case-insensitive (e.g. A = 4 and a = 4).