Tried to add the following code to add validation for street, but it's not work. How to add the validation for street? Thanks.
<page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" layout="1column" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
<body>
<referenceBlock name="checkout.root">
<arguments>
<argument name="jsLayout" xsi:type="array">
<item name="components" xsi:type="array">
<item name="checkout" xsi:type="array">
<item name="children" xsi:type="array">
<item name="steps" xsi:type="array">
<item name="children" xsi:type="array">
<item name="shipping-step" xsi:type="array">
<item name="children" xsi:type="array">
<item name="shippingAddress" xsi:type="array">
<item name="children" xsi:type="array">
<item name="shipping-address-fieldset" xsi:type="array">
<item name="children" xsi:type="array">
<item name="company" xsi:type="array">
<item name="visible" xsi:type="boolean">false</item>
</item>
<item name="firstname" xsi:type="array">
<item name="validation" xsi:type="array">
<item name="validate-alpha" xsi:type="string">true</item>
</item>
</item>
<item name="lastname" xsi:type="array">
<item name="validation" xsi:type="array">
<item name="validate-alpha" xsi:type="string">true</item>
</item>
</item>
<item name="flat" xsi:type="array">
<item name="validation" xsi:type="array">
<item name="validate-alphanum-with-spaces" xsi:type="string">true</item>
</item>
</item>
<item name="floor" xsi:type="array">
<item name="validation" xsi:type="array">
<item name="validate-alphanum-with-spaces" xsi:type="string">true</item>
</item>
</item>
<item name="building" xsi:type="array">
<item name="validation" xsi:type="array">
<item name="validate-alphanum-with-spaces" xsi:type="string">true</item>
</item>
</item>
<item name="street" xsi:type="array">
<!-- <item name="children" xsi:type="array">
<item name="0" xsi:type="array">-->
<item name="validation" xsi:type="array">
<item name="validate-hk-address" xsi:type="string">true</item>
</item>
<!-- </item>
<item name="1" xsi:type="array">
<item name="validation" xsi:type="array">
<item name="validate-hk-address" xsi:type="string">true</item>
</item>
</item>
</item>-->
</item>
<item name="city" xsi:type="array">
<item name="validation" xsi:type="array">
<item name="validate-hk-address" xsi:type="string">true</item>
</item>
</item>
<item name="telephone" xsi:type="array">
<item name="validation" xsi:type="array">
<item name="validate-hk-phone-number" xsi:type="string">true</item>
</item>
</item>
</item>
</item>
</item>
</item>
</item>
</item>
</item>
</item>
</item>
</item>
</item>
</argument>
</arguments>
</referenceBlock>
</body>
</page>