code: def _get_transmissions(self):
          
          # pylint: disable=invalid-name
          ContentMetadataItemTransmission = apps.get_model(
              'integrated_channel',
              'ContentMetadataItemTransmission'
          )
          return ContentMetadataItemTransmission.objects.filter(
              enterprise_customer=self.enterprise_configuration.enterprise_customer,
              integrated_channel_code=self.enterprise_configuration.channel_code()
          )
docs: Return the ContentMetadataItemTransmision models for previously
          transmitted content metadata items.