SVG画图stroke为none时为什么还有一条线？如何解决？

<svg width="250px" height="250px">
        <circle cx = 108 cy = 108 r = 108 stroke = "none" fill = "#000"></circle>
        <path d = "M108 108 A50 50 0 0 1 108 0 " stroke = "none" fill = "#fff"/>
        <path d = "M108 0 A50 50 0 0 1 108 216 " stroke = "none" fill = "#fff"/>
        <path d = "M108 108 A50 50 0 0 1 108 216 " stroke = "none" fill = "#000"/>
        <circle cx = 108 cy = 54 r = 12 stroke="none" fill = "#000"/>
        <circle cx = 108 cy = 162 r = 12 stroke="none" fill = "#fff"/>
    </svg>

如何取消中间的那根细线？
要是能顺便告诉我这个细线为什么会产生就更好啦！

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我把你的代码复制到本地，没有看到线。