code: def send(self, transactions):
          
          txn_signatures = [txn.header_signature for txn in transactions]
          header = BatchHeader(
              signer_public_key=self._identity_signer.get_public_key().as_hex(),
              transaction_ids=txn_signatures
          ).SerializeToString()
  
          signature = self._identity_signer.sign(header)
          batch = Batch(
              header=header,
              transactions=transactions,
              header_signature=signature)
  
          self._batch_sender.send(batch)
docs: Package up transactions into a batch and send them to the
          network via the provided batch_sender.
          :param transactions: list of transactions to package and broadcast.
          :return: None