为什么这个Python函数执行后不释放内存?

Why does this Python function not release memory after execution?

我有一个 Python 脚本,它查看一个 XML 文件,该文件已通过 Beautiful Soup 传递以寻找文本术语。然后我遍历到我想要提取的值和 return 字符串。这行得通,但是因为我在程序主循环中添加了对该函数的调用,所以我最终遇到了 MemoryError 问题。查看 Windows 任务管理器我发现每次调用后内存都没有释放,系统内存不足。问题似乎出在 'return myLink.string' 行。这是否包含对内存中对象的引用,我该如何解决这个问题?

def FindUptime(soup):
    link = soup.find(text=re.compile("Uptime"))
    if link:
        myLink = link.parent
        myLink = myLink.next_sibling
        if myLink.string == "Up:":
            myLink = myLink.next_sibling
            myLink = myLink.next_element
        else:
            print "Can't find Up: term"
        return myLink.string
    else:
        print "Can't find Uptime"
        return ""

调用者

readings[sensorIds[i][SENSOR_NAME]] = FindUptime(soup)

修改为...

def FindUptime(soup):
    link = soup.find(text=re.compile("Uptime"))
    if link:
        myLink = link.parent
        myLink = myLink.next_sibling
        if myLink.string == "Up:":
            myLink = myLink.next_sibling
            myLink = myLink.next_element
        else:
            print "Can't find Up: term"
        uptime = str(myLink.string) # added
        return uptime
    else:
        print "Can't find Uptime"
    return ""