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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def pypackable(name, pytype, format):
 """ Create a "mix-in" class with a python type and a Packable with the given struct format """

    size, items = _formatinfo(format)
    return type(Packable)(name, (pytype, Packable), {
        '_format_': format,
        '_size_': size,
        '_items_': items,
    })