code: def build_validation_data_loader(self):
      x_val = np.ones((64, 8, 8))
      y_val = np.ones((64, 8, 8))
      return (x_val, y_val)
  
file_path: determined/harness/tests/experiment/fixtures/keras_tf2_disabled_no_op/model_def.py
imports: import numpy
  import tensorflow
  from determined.keras import TFKerasTrial, TFKerasTrialContext
label_desc: Use image node_id 4 for calling the NoopKerasTrial obj's underlying member method code with example usage: obj.build_validation_data_loader() and returns: x_val,  y_val