def _format_object_mask(objectmask):
    """Format the new style object mask.

    This wraps the user mask with mask[USER_MASK] if it does not already
    have one. This makes it slightly easier for users.

    :param objectmask: a string-based object mask

    """
    objectmask = objectmask.strip()
    if not objectmask.startswith('mask') and not objectmask.startswith('['):
        objectmask = 'mask[%s]' % objectmask
    return objectmask
