docs: def merge_entity(self, entity, if_match='*'):
          '''
          Adds a merge entity operation to the batch. See 
          :func:`~azure.storage.table.tableservice.TableService.merge_entity` for more 
          information on merges.
          
          The operation will not be executed until the batch is committed.
  
          :param entity:
              The entity to merge. Could be a dict or an entity object. 
              Must contain a PartitionKey and a RowKey.
          :type entity: a dict or :class:`azure.storage.table.models.Entity`
          :param str if_match:
              The client may specify the ETag for the entity on the 
              request in order to compare to the ETag maintained by the service 
              for the purpose of optimistic concurrency. The merge operation 
              will be performed only if the ETag sent by the client matches the 
              value maintained by the server, indicating that the entity has 
              not been modified since it was retrieved by the client. To force 
              an unconditional merge, set If-Match to the wildcard character (*).
          '''
          request = _merge_entity(entity, if_match)
          self._add_to_batch(entity['PartitionKey'], entity['RowKey'], request)