code: def test_not_an_input_layer_exception(self):
      network = layers.join(
          layers.Input(10),
          layers.Sigmoid(2, name="sigmoid-2"),
          layers.Sigmoid(10),
      )
      x_test = asfloat(np.ones((7, 5)))
  
      with self.assertRaisesRegexp(ValueError, "is not an input layer"):
          network.output({"sigmoid-2": x_test})
  
file_path: neupy/tests/layers/graph/test_usage.py
imports: import numpy
  from neupy import layers
  from neupy.utils import asfloat
  from base import BaseTestCase
label_desc: Use image node_id 5 for calling the UsageTestCase obj's underlying member method code with example usage: obj.test_not_an_input_layer_exception() without return types