Sum of Prime Numbers

Create a function that takes a list of numbers and returns the sum of all prime numbers in the list.

Examples

sum_primes([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) ➞ 17

sum_primes([2, 3, 4, 11, 20, 50, 71]) ➞ 87

sum_primes([]) ➞ None

Notes

• Given numbers won't exceed 101.
• A prime number is a number which has exactly two divisors.