I am trying to override core interface of Customer Group.

I add my custom get and set methods to core Api interface.

> 
> Vendor\magento\customer-module\Api\Data\GroupInterface.php
> 
> 
> 

Where its working fine.

But when i am trying to override it its doesn't seems to be work.

Here i am sharing my module code.

> 
> ZeroCool\AdvacedReviews\Api\Data\GroupInterface.php
> 
> 
> 

```
<?php

namespace ZeroCool\AdvancedReviews\Api\Data\GroupInterface;

interface GroupInterface extends ExtensibleDataInterface
{   
const SHIPPING_METHOD = 'shipping_method';

/**
 * Get shipping method
 *
 * @return string
 */
public function getShippingMethod();

/**
 * Set shipping method
 *
 * @param int $shippingMethod
 * @return $this
 */
public function setShippingMethod($shippingMethod);

}

```

> 
> ZeroCool\AdvancedReviews\etc\di.xml
> 
> 
> 

```
<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
<type name="Magento\Customer\Block\Adminhtml\Group\Edit\Form">
    <plugin name="add_form_field" type="ZeroCool\AdvancedReviews\Model\Plugin\Form" sortOrder="1"/>
</type>
<type name="Magento\Customer\Controller\Adminhtml\Group\Save">
    <plugin name="save_field" type="ZeroCool\AdvancedReviews\Model\Plugin\Form" sortOrder="1"/>
</type>
<preference for="Magento\Customer\Model\Data\Group" type="ZeroCool\AdvancedReviews\Model\Data\Group" /> 
<preference for="Magento\Customer\Api\Data\GroupInterface" type="ZeroCool\AdvancedReviews\Api\Data\GroupInterface" /> 

```

There's also one question available but it doesn't have any answers till now.

[Stack Exchange](https://magento.stackexchange.com/questions/183940/overriding-or-extending-core-interfaces)

Thanks in advance.