title: How to create a new attribute with multichoice of woocomerce product attribute?
body: <p>Firstly, I want to create a filter for a certain product category in woocomerce with some attributes of products. For example: A filter for a product category of Wifi Access point, which have 2 attributes (Wifi Standard, Operation Mode)
  <a href="https://i.stack.imgur.com/tHlVp.png" rel="nofollow noreferrer">Filter</a></p>
  <ol>
  <li><p>Wifi Standard values (and they are multichoices):</p>
  <p>802.11a/b/g/n
  802.11ac Wave 1
  802.11ac Wave 2
  802.11ax (Wifi 6)</p>
  </li>
  <li><p>Operation Mode (Single Choice)<br />
  Standalone
  Controller Base</p>
  </li>
  </ol>
  <p>Secondly, I hope that I can create filter with many attributes (can choose multichoice or single)
  .But now, I don't know how to create options(multichoice or single choice) for these attributes or where I can mofidy the code from the woocommerce plugin.</p>
  <p><em>(In attributes tab, woocommerce product category has a same filed, which is called Archive checkbox.)</em>
  <a href="https://i.stack.imgur.com/Gvcqx.png" rel="nofollow noreferrer">the same option</a></p>
  <p>Please give me some advices for this situation.</p>
  <p>Thank you</p>