첫번째

def solution(id_pw, db):

for i,j in db:
    a_check, b_check = id_pw
    if i == a_check and j == b_check:
        return "login"
    elif i == a_check and j != b_check:
        return "wrong pw"

return "fail“

개선

def solution(id_pw, db):

for i,j in db:
    a_check, b_check = id_pw
    if i == a_check:
        if j == b_check:
            return "login"
        else :
            return "wrong pw"

return "fail“