def tag_for(name, *a, **k):
    """create a zoom tag

    >>> tag_for('name')
    '<dz:name>'

    >>> tag_for('name', default=1)
    '<dz:name default=1>'
    """
    return '<dz:{}{}{}>'.format(
        name,
        a and (' ' + ' '.join(str(a))) or '',
        k and (' ' + ' '.join(
            '{}={!r}'.format(k, v) for k, v in sorted(k.items())
        )) or ''
    )