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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 get_routes(iface):
    '''
    Return the contents of the interface routes script.

    CLI Example:

    .. code-block:: bash

        salt '*' ip.get_routes eth0
    '''
    path = os.path.join(_RH_NETWORK_SCRIPT_DIR, 'route-{0}'.format(iface))
    path6 = os.path.join(_RH_NETWORK_SCRIPT_DIR, 'route6-{0}'.format(iface))
    routes = _read_file(path)
    routes.extend(_read_file(path6))
    return routes