<value><string>python:[(o.getProperty("title"), o.getProperty("id")) for o in context.getPortalObject().portal_catalog(portal_type="Project", validation_state="validated", select_list=("id", "title"))]</string></value>
<value><stringencoding="cdata"><![CDATA[
python: len(field.get_value(\'items\') or []) <= 2 and field.get_value(\'items\')[-1][1] or None
<value><string>python: [("", "")] + [(o.getProperty("title"), o.getProperty("id")) for o in context.getPortalObject().portal_catalog(portal_type="Project", validation_state="validated", select_list=("id", "title"))]</string></value>