code: def test_subtract_layer_inputs_length_errors(self):
      shape = (4, 5)
      input_1 = layers.Input(shape=shape)
      input_2 = layers.Input(shape=shape)
      input_3 = layers.Input(shape=shape)
  
      with self.assertRaisesRegex(
          ValueError, "layer should be called on exactly 2 inputs"
      ):
          layers.Subtract()([input_1, input_2, input_3])
      with self.assertRaisesRegex(
          ValueError, "layer should be called on exactly 2 inputs"
      ):
          layers.Subtract()([input_1])
  
file_path: keras/keras/layers/merging/merging_test.py
imports: import numpy
  import pytest
  from absl.testing import parameterized
  from keras import backend
  from keras import layers
  from keras import models
  from keras import testing
label_desc: Use image node_id 5 for calling the MergingLayersTest obj's underlying member method code with example usage: obj.test_subtract_layer_inputs_length_errors() without return types