Question: 
Write a python function to find the sum of the three lowest positive numbers from a given list of numbers.


Model's Code:
def sum_three_smallest_nums(arr):
    positive_nums = [num for num in arr if num > 0]
    return sum(sorted(positive_nums)[:3]) if len(positive_nums) >= 3 else None



Sample Correct Code:
def sum_three_smallest_nums(lst):
	return sum(sorted([x for x in lst if x > 0])[:3])


Asserts:
assert sum_three_smallest_nums([10,20,30,40,50,60,7]) == 37
assert sum_three_smallest_nums([1,2,3,4,5]) == 6
assert sum_three_smallest_nums([0,1,2,3,4,5]) == 6


Tests:
Test 1 of 3: PASS
Test 2 of 3: PASS
Test 3 of 3: PASS

Test 340 of 974: 246/340 (72.35294117647058%): success