code: def _create_header(self):
          
          # Retrieve the node to which we will append the group header.
          CstmrDrctDbtInitn_node = self._xml.find('CstmrDrctDbtInitn')
  
          # Create the header nodes.
          GrpHdr_node = ET.Element("GrpHdr")
          MsgId_node = ET.Element("MsgId")
          CreDtTm_node = ET.Element("CreDtTm")
          NbOfTxs_node = ET.Element("NbOfTxs")
          CtrlSum_node = ET.Element("CtrlSum")
          InitgPty_node = ET.Element("InitgPty")
          Nm_node = ET.Element("Nm")
          SupId_node = ET.Element("Id")
          OrgId_node = ET.Element("OrgId")
          Othr_node = ET.Element("Othr")
          Id_node = ET.Element("Id")
  
          # Add data to some header nodes.
          MsgId_node.text = self.msg_id
          CreDtTm_node.text = datetime.datetime.now().strftime('%Y-%m-%dT%H:%M:%S')
          Nm_node.text = self._config['name']
          Id_node.text = self._config['creditor_id']
  
          # Append the nodes
          Othr_node.append(Id_node)
          OrgId_node.append(Othr_node)
          SupId_node.append(OrgId_node)
          InitgPty_node.append(Nm_node)
          InitgPty_node.append(SupId_node)
          GrpHdr_node.append(MsgId_node)
          GrpHdr_node.append(CreDtTm_node)
          GrpHdr_node.append(NbOfTxs_node)
          GrpHdr_node.append(CtrlSum_node)
          GrpHdr_node.append(InitgPty_node)
  
          # Append the header to its parent
          CstmrDrctDbtInitn_node.append(GrpHdr_node)
docs: Function to create the GroupHeader (GrpHdr) in the
          CstmrDrctDbtInit Node