code: def _to_DOM(self):
          
          root_node = ET.Element('station')
          created_at_node = ET.SubElement(root_node, "created_at")
          created_at_node.text = \
              timeformatutils.to_ISO8601(self.created_at)if self.created_at is not None else 'null'
          updated_at_node = ET.SubElement(root_node, "updated_at")
          updated_at_node.text = \
              timeformatutils.to_ISO8601(self.updated_at)if self.updated_at is not None else 'null'
          station_id_node = ET.SubElement(root_node, 'id')
          station_id_node.text = str(self.id)
          station_id_node = ET.SubElement(root_node, 'external_id')
          station_id_node.text = str(self.external_id)
          station_name_node = ET.SubElement(root_node, 'name')
          station_name_node.text = str(self.name) if self.name is not None else 'null'
          lat_node = ET.SubElement(root_node, 'lat')
          lat_node.text = str(self.lat)
          lon_node = ET.SubElement(root_node, 'lon')
          lon_node.text = str(self.lon)
          alt_node = ET.SubElement(root_node, 'alt')
          alt_node.text = str(self.alt) if self.alt is not None else 'null'
          rank_node = ET.SubElement(root_node, 'rank')
          rank_node.text = str(self.rank) if self.rank is not None else 'null'
  
          return root_node
docs: Dumps object data to a fully traversable DOM representation of the
          object.
  
          :returns: a ``xml.etree.Element`` object