def add_default_layout():
    """Add an empty layout as default."""
    from collective.cover.config import EMPTY_LAYOUT
    from collective.cover.controlpanel import ICoverSettings
    from plone.registry.interfaces import IRegistry
    from zope.component import getUtility
    registry = getUtility(IRegistry)
    settings = registry.forInterface(ICoverSettings)
    default = u'Empty layout'
    if settings.layouts.get(default) == u'[]':
        settings.layouts[default] = EMPTY_LAYOUT
