code: def test_reshape_unknown_shape(self):
      network = layers.join(
          layers.Input((None, 20)),
          layers.Reshape(),
      )
      self.assertShapesEqual(network.output_shape, (None, None))
  
      x = np.random.random((7, 12, 20))
      y = self.eval(network.output(x))
      self.assertEqual(y.shape, (7, 12 * 20))
  
imports: import numpy
  from neupy import layers
  from neupy.utils import asfloat, tf_utils
  from neupy.exceptions import LayerConnectionError
  from base import BaseTestCase
label_desc: Use image node_id 3 for calling the ReshapeLayerTestCase obj's underlying member method code with example usage: obj.test_reshape_unknown_shape() without return types