Signal for creating OAI-PMH sets during community creation.

def create_oaipmh_set(mapper, connection, community):
    """Signal for creating OAI-PMH sets during community creation."""
    from invenio_oaiserver.models import OAISet
    with db.session.begin_nested():
        obj = OAISet(spec=community.oaiset_spec,
                     name=community.title,
                     description=community.description)
        db.session.add(obj)