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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 create_downloader_of_type(type_name):
 """ Create an instance of the downloader with the given name. Args: type_name: The name of a downloader. Returns: An instance of the downloader with the given type. """

    downloaders = available_downloaders()

    if type_name not in downloaders.keys():
        raise UnknownDownloaderException('Unknown downloader: %s' % (type_name,))

    return downloaders[type_name]()