code: def build_checkboard(n, m, k=8):
      x = np.zeros((n, m))
      x[k :: k * 2, ::k] = 1
      x[:: k * 2, k :: k * 2] = 1
      return x
  
imports: import os
  from pathlib import Path
  from typing import Callable, Dict, List, Tuple
  import numpy
  import pytest
  import torch
  from flash import Trainer
  from flash.core.data.io.input import DataKeys
  from flash.core.data.io.input_transform import InputTransform
  from flash.core.data.transforms import ApplyToKeys
  from flash.core.utilities.imports import _FIFTYONE_AVAILABLE, _MATPLOTLIB_AVAILABLE, _PIL_AVAILABLE, _SEGMENTATION_MODELS_AVAILABLE, _TOPIC_IMAGE_AVAILABLE
  from flash.image import SemanticSegmentation, SemanticSegmentationData
label_desc: Use image node_id 1 for calling a global function with example usage: build_checkboard(n, m, k) and returns: x