def canonical_property(archive, name):
    """
    Make sure "core" is added to properties without namespace.
    """
    if name in ['count', 'tag']:
        return name
    metadata = archive._namespace_schemas
    if name == '*':
        name = '*.*'
    else:
        split_name = name.split('.')
        if split_name[0] not in metadata and (split_name[0] in metadata[
            'core'] or split_name[0] == 'validity_duration'):
            name = '%s.%s' % ('core', name)
    return name
