count_users 函数通过遍历组中的每个成员，递归地统计属于公司系统中某个组的用户数量，如果其中一个是组，则递归调用该函数并对成员进行计数。但它有一个错误！你能发现问题并解决它吗？
def count_users(group):
count = 0
for member in get_members(group):
count += 1
if is_group(member):
count += count_users(member)
return count
print(count_users("sales")) # Should be 3
print(count_users("engineering")) # Should be 8
print(count_users("everyone")) # Should be 18