docs: async def build_get_txn_fees_req(wallet_handle: int,
                                   submitter_did: str,
                                   payment_method: str) -> str:
      """
      Builds Indy request for getting fees for transactions in the ledger
  
      :param wallet_handle: wallet handle (created by open_wallet).
      :param submitter_did : (Option) DID of request sender
      :param payment_method: Payment method to use (for example, 'sov').
      :return: set_txn_fees_json: Indy request for setting fees for transactions in the ledger
      """
  
      logger = logging.getLogger(__name__)
      logger.debug("build_get_txn_fees_req: >>> wallet_handle: %r, submitter_did: %r, payment_method: %r",
                   wallet_handle,
                   submitter_did,
                   payment_method)
  
      if not hasattr(build_get_txn_fees_req, "cb"):
          logger.debug("build_get_txn_fees_req: Creating callback")
          build_get_txn_fees_req.cb = create_cb(CFUNCTYPE(None, c_int32, c_int32, c_char_p))
  
      c_wallet_handle = c_int32(wallet_handle)
      c_submitter_did = c_char_p(submitter_did.encode('utf-8')) if submitter_did is not None else None
      c_payment_method = c_char_p(payment_method.encode('utf-8'))
  
      get_txn_fees_json = await do_call('indy_build_get_txn_fees_req',
                                        c_wallet_handle,
                                        c_submitter_did,
                                        c_payment_method,
                                        build_get_txn_fees_req.cb)
  
      res = get_txn_fees_json.decode()
      logger.debug("build_get_txn_fees_req: <<< res: %r", res)
      return res