code: def test_causal_conv_use_bias_false(self):
      layer = tl.CausalConv(filters=30, kernel_width=3, use_bias=False)
      x = np.ones((9, 5, 20))
      layer.init(shapes.signature(x))
  
      y = layer(x)
      self.assertEqual(y.shape, (9, 5, 30))
  
      self.assertEqual(layer.weights.shape, (3, 20, 30))
  
file_path: trax/trax/layers/convolution_test.py
imports: from absl.testing import absltest
  import numpy
  from trax import shapes
  import trax.layers
label_desc: Use image node_id 2 for calling the CausalConvolutionTest obj's underlying member method code with example usage: obj.test_causal_conv_use_bias_false() without return types