Zendesk\API\Resources\ResourceAbstract::getResourceNameFromClass PHP Method

    protected function getResourceNameFromClass()
    {
        $namespacedClassName = get_class($this);
        $resourceName = join('', array_slice(explode('\\', $namespacedClassName), -1));
        // This converts the resource name from camel case to underscore case.
        // e.g. MyClass => my_class
        $underscored = strtolower(preg_replace('/(?<!^)([A-Z])/', '_$1', $resourceName));
        return strtolower($underscored);
    }

 /**
  * Appends the channels/voice/ prefix to resource names
  * @return string
  */
 protected function getResourceNameFromClass()
 {
     $resourceName = parent::getResourceNameFromClass();
     return 'channels/voice/' . $resourceName;
 }