code: def layers(self):
      l_1 = lasagne.layers.InputLayer((None, 10))
      l_2 = lasagne.layers.DenseLayer(l_1, num_units=20)
      l_3 = lasagne.layers.DenseLayer(l_2, num_units=30)
      return l_1, l_2, l_3
  
file_path: Lasagne/lasagne/tests/test_regularization.py
imports: import pytest
  import numpy
  import theano.tensor
  import lasagne
  from collections import OrderedDict
  from theano.scan_module.scan_utils import equal_computations
  from mock import Mock
label_desc: Use image node_id 1 for calling the TestRegularizationHelpers obj's underlying member method code with example usage: obj.layers() and returns: l_1,  l_2,  l_3