code: def test_plot_prediction_grid():
      model = get_model()
      try:
          plot_prediction_grid(model, [3, 4], (3, 5))
          assert False  # Above should throw a value error
      except ValueError:
          pass
      except Exception:
          assert False  # An error occurred
  
      plt.show = lambda: None
  
      image = get_image()
      plot_prediction_grid(
          model, [image], (1, 1), figsize=(20, 10)
      )  # Shouldn't throw an error
  
      # Ensure it works when the model makes no predictions
      model._model.forward = empty_predictor
      plot_prediction_grid(model, [image], dim=None)
  
imports: import os
  from .helpers import get_image, get_model, empty_predictor
  from detecto.visualize import *
label_desc: Use image node_id 2 for calling a global function with example usage: test_plot_prediction_grid() without return types