class ProjectsVocabulary(object):
    interface.implements(IContextSourceBinder)

    def __call__(self, context):
        terms = []
        catalog = getToolByName(context, 'portal_catalog')                                     query = {}
        query["portal_type"] = 'Project'
        results = catalog(query)
        for project in results:
            terms.append(
                SimpleVocabulary.createTerm(
                    project.project_id,
                    str(project.project_id),
                    project.title
                )
            )
        return SimpleVocabulary(terms)