缓冲的代码不能附加块-Pug

Question

这是什么意思？第13行是“ a（href ='/ current / post /'+ post.key）”

mixin post(post)

    .col-lg-4.col-md-4
        .panel.panel-default
            .panel-body
                a(href='/current/post/' + post.key)
                    if post.image.exists
                        img(src=post._.image.fit()).img-responsive
                    else
                        img(src="http://placehold.it/250x250").img-responsive
            .panel-footer
                != post.content.brief
                    a(href='/current/post/' + post.key)
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