code: public void unregisterTaskDef(String taskType) {
          Preconditions.checkArgument(StringUtils.isNotBlank(taskType), "Task type cannot be blank");
          stub.deleteTask(MetadataServicePb.DeleteTaskRequest.newBuilder()
                  .setTaskType(taskType)
                  .build()
          );
      }
docs: Removes the task definition of a task type from the conductor server.
  Use with caution.
  
  @param taskType Task type to be unregistered.