code: def _partition_items(self, channel_metadata_item_map):
          
          items_to_create = {}
          items_to_update = {}
          items_to_delete = {}
          transmission_map = {}
          export_content_ids = channel_metadata_item_map.keys()
  
          # Get the items that were previously transmitted to the integrated channel.
          # If we are not transmitting something that was previously transmitted,
          # we need to delete it from the integrated channel.
          for transmission in self._get_transmissions():
              transmission_map[transmission.content_id] = transmission
              if transmission.content_id not in export_content_ids:
                  items_to_delete[transmission.content_id] = transmission.channel_metadata
  
          # Compare what is currently being transmitted to what was transmitted
          # previously, identifying items that need to be created or updated.
          for item in channel_metadata_item_map.values():
              content_id = item.content_id
              channel_metadata = item.channel_metadata
              transmitted_item = transmission_map.get(content_id, None)
              if transmitted_item is not None:
                  if diff(channel_metadata, transmitted_item.channel_metadata):
                      items_to_update[content_id] = channel_metadata
              else:
                  items_to_create[content_id] = channel_metadata
  
          LOGGER.info(
              'Preparing to transmit creation of [%s] content metadata items with plugin configuration [%s]: [%s]',
              len(items_to_create),
              self.enterprise_configuration,
              items_to_create.keys(),
          )
          LOGGER.info(
              'Preparing to transmit update of [%s] content metadata items with plugin configuration [%s]: [%s]',
              len(items_to_update),
              self.enterprise_configuration,
              items_to_update.keys(),
          )
          LOGGER.info(
              'Preparing to transmit deletion of [%s] content metadata items with plugin configuration [%s]: [%s]',
              len(items_to_delete),
              self.enterprise_configuration,
              items_to_delete.keys(),
          )
  
          return items_to_create, items_to_update, items_to_delete, transmission_map
docs: Return items that need to be created, updated, and deleted along with the
          current ContentMetadataItemTransmissions.