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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:
 async def list_pairwise(wallet_handle: int) -> str: """ Get list of saved pairwise. :param wallet_handle: wallet handler (created by open_wallet). :return: pairwise_list: list of saved pairwise """


    logger = logging.getLogger(__name__)
    logger.debug("list_pairwise: >>> wallet_handle: %r", wallet_handle)

    if not hasattr(list_pairwise, "cb"):
        logger.debug("list_pairwise: Creating callback")
        list_pairwise.cb = create_cb(CFUNCTYPE(None, c_int32, c_int32, c_char_p))

    c_wallet_handle = c_int32(wallet_handle)

    pairwise_list = await do_call('indy_list_pairwise',
                                  c_wallet_handle,
                                  list_pairwise.cb)

    res = pairwise_list.decode()
    logger.debug("list_pairwise: <<< res: %r", res)
    return res