def sortable_title ( instance ) : title = plone_sortable_title ( instance ) if safe_callable ( title ) : title = title ( ) return title . lower ( )
callable title objects in python
Uses the default Plone sortable_text index lower - case
def sortable_title(instance):
    """Uses the default Plone sortable_text index lower-case
    """
    title = plone_sortable_title(instance)
    if safe_callable(title):
        title = title()
    return title.lower()