Document Filter condition ERROR: undefined interceptor

[roccapl_]

I'm learning how to use operations and chains.

I used this nuxeo answer post as a reference: http://answers.nuxeo.com/questions/3596/filter-in-event-handler

I tried to implement a simple Filter like this

<operation id="Document.Filter" >
  	<param type="string" name="condition">@{Document.getPropertyValue("dc:title") == "test"}</param>
</operation>

but this is the error I get:

2012-11-08 15:53:54,547 ERROR [org.nuxeo.ecm.automation.core.operations.document.FilterDocuments]

[Error: reference to undefined interceptor: {Document.getPropertyValue("dc:title") == "test"}]

[Near : {... tyValue("dc:title") == "test" ....}] [Line: 1, Column: 50]

thank in advance to anyone who could help.