Parses response for Indy request for getting fees

    :param payment_method: Payment method to use (for example, 'sov').
    :param resp_json: response for Indy request for getting fees
    :return: fees_json: {
       txnType1: amount1,
       txnType2: amount2,
       .................
       txnTypeN: amountN,
     }

async def parse_get_txn_fees_response(payment_method: str,
                                      resp_json: str) -> str:
    """
    Parses response for Indy request for getting fees

    :param payment_method: Payment method to use (for example, 'sov').
    :param resp_json: response for Indy request for getting fees
    :return: fees_json: {
       txnType1: amount1,
       txnType2: amount2,
       .................
       txnTypeN: amountN,
     }
    """

    logger = logging.getLogger(__name__)
    logger.debug("parse_get_txn_fees_response: >>> payment_method: %r, resp_json: %r",
                 payment_method,
                 resp_json)

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

    c_payment_method = c_char_p(payment_method.encode('utf-8'))
    c_resp_json = c_char_p(resp_json.encode('utf-8'))

    fees_json = await do_call('indy_parse_get_txn_fees_response',
                              c_payment_method,
                              c_resp_json,
                              parse_get_txn_fees_response.cb)

    res = fees_json.decode()
    logger.debug("parse_get_txn_fees_response: <<< res: %r", res)
    return res