ElementUi如何使用slot="header"？

https://segmentfault.com/q/1010000016891804

<el-table-column  prop="condition"  label="状态" width="120" align="center" >
  <template slot="header" slot-scope="slot">
    <div>
      <span>状态</span>
      <el-tooltip class="tooltip" effect="light" content="指...的状态" placement="top">

        <i class="el-icon-question"></i>
        
      </el-tooltip>

    </div>
  </template>
  <template slot-scope="scope"> 
    <span :class="scope.row.condition">{{ scope.row.condition}}</span>  
  </template>
</el-table-column>