def py_default(type_name):
    """Get the Python default value for a given model type.

        >>> py_default('string')
        '\'string\''
        >>> py_default('list')
        '[...]'
        >>> py_default('unknown')
        '...'

    :rtype: string
    """
    return {
        'double': '123.0',
        'long': '123',
        'integer': '123',
        'string': "'string'",
        'blob': "b'bytes'",
        'boolean': 'True|False',
        'list': '[...]',
        'map': '{...}',
        'structure': '{...}',
        'timestamp': 'datetime(2015, 1, 1)',
    }.get(type_name, '...')