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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 set_style(network_id, ndex_cred=None, template_id=None):
 """Set the style of the network to a given template network's style Parameters network_id : str The UUID of the NDEx network whose style is to be changed. ndex_cred : dict A dictionary of NDEx credentials. template_id : Optional[str] The UUID of the NDEx network whose style is used on the network specified in the first argument. """

    if not template_id:
        template_id = "ea4ea3b7-6903-11e7-961c-0ac135e8bacf"

    server = 'http://public.ndexbio.org'
    username, password = get_default_ndex_cred(ndex_cred)

    source_network = ndex2.create_nice_cx_from_server(username=username,
                                                      password=password,
                                                      uuid=network_id,
                                                      server=server)

    source_network.apply_template(server, template_id)

    source_network.update_to(network_id, server=server, username=username,
                             password=password)