def func_unset(parser, name):
    """Unsets the variable ``name``."""
    if name.startswith('_'):
        name = '~' + name[1:]
    if name in ('performer:*', 'comment:*', 'lyrics:*'):
        name = name[:-1]
        for key in list(parser.context.keys()):
            if key.startswith(name):
                del parser.context[key]
        return ''
    try:
        del parser.context[name]
    except KeyError:
        pass
    return ''
