프로그래머스 - 두 개 뽑아서 더하기

# python 3

def solution(numbers):
    answer = []
    for i in range(len(numbers)):
        for j in range(i+1,len(numbers)):
            out = numbers[i] + numbers[j]
            if not out in answer:
                answer.append(out)
    answer.sort()    
    return answer