symfony/tests/Symfony/Tests/Component/DependencyInjection/Fixtures/xml/interfaces1.xml

<?xml version="1.0" ?>

<container xmlns="http://symfony.com/schema/dic/services"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">
  
  <services>
    <service id="foo" class="FooClass" />
  </services>
  <interfaces>
    <interface class="FooClass">
      <call method="setBar">
        <argument>correct</argument>
      </call>
    </interface>
  </interfaces>
</container>