def new_dataset(args):
    """
    lexibank new-dataset OUTDIR [ID]
    """
    if not args.args:
        raise ParserError('you must specify an existing directory')
    outdir = Path(args.args.pop(0))
    if not outdir.exists():
        raise ParserError('you must specify an existing directory')

    id_pattern = re.compile('[a-z_0-9]+$')
    md = {}
    if args.args:
        md['id'] = args.args.pop(0)
    else:
        md['id'] = input('Dataset ID: ')

    while not id_pattern.match(md['id']):
        print('dataset id must only consist of lowercase ascii letters, digits and _ (underscore)!')
        md['id'] = input('Dataset ID: ')

    outdir = outdir / md['id']
    if not outdir.exists():
        outdir.mkdir()

    for key in ['title', 'url', 'license', 'conceptlist', 'citation']:
        md[key] = input('Dataset {0}: '.format(key))

    # check license!
    # check conceptlist!

    for path in Path(pylexibank.__file__).parent.joinpath('dataset_template').iterdir():
        if path.is_file():
            if path.suffix in ['.pyc']:
                continue  # pragma: no cover
            target = path.name
            content = read_text(path)
            if '+' in path.name:
                target = re.sub(
                    '\+([a-z]+)\+',
                    lambda m: '{' + m.groups()[0] + '}',
                    path.name
                ).format(**md)
            if target.endswith('_tmpl'):
                target = target[:-5]
                content = content.format(**md)
            write_text(outdir / target, content)
        else:
            target = outdir / path.name
            if target.exists():
                shutil.rmtree(str(target))
            shutil.copytree(str(path), str(target))
    del md['id']
    jsonlib.dump(md, outdir / 'metadata.json', indent=4)
lexibank new-dataset OUTDIR [ID]