element-ui Cascader 级联选择器多级禁用

                      

<template>
    <div>
      <el-cascader 
      ref="cascader" 
      v-model="checked" 
      :options="options" 
      :props="props"
      clearable
      @change="handleChange" />
    </div>
</template>

<script>
export default {
    data() {
        return {
            props: {
                multiple: true,
                emitPath: false
            },
            checked: [],
            options: [{
                value: 1,
                label: '东南',
                disabled: false,
                children: [{
                    value: 2,
                    label: '上海',
                    disabled: false,
                    children: [