code: def test_pick_setter(self):
      invalid_name = "nonexistent"
      self.assertNotIn(invalid_name, self.link.layer_names)
      expected_message_pattern = str.format(
          "^Invalid layer name .{:s}.$", invalid_name
      )
      with self.assertRaisesRegex(ValueError, expected_message_pattern):
          self.link.pick = invalid_name
      invalid_names = "nonexistent", "nonexistent2"
      for n in invalid_names:
          self.assertNotIn(n, self.link.layer_names)
      expected_message_pattern = str.format(
          "^Invalid layer name .{:s}.$", invalid_names[0]
      )
      with self.assertRaisesRegex(ValueError, expected_message_pattern):
          self.link.pick = invalid_names
  
imports: import numpy
  import unittest
  import chainer
  from chainer.backends.cuda import to_cpu
  from chainer.function import Function
  from chainer import testing
  from chainer.testing import attr
  from chainercv.links import PickableSequentialChain
  from chainercv.utils.testing import ConstantStubLink
label_desc: Use image node_id 3 for calling the PickableSequentialChainTestBase obj's underlying member method code with example usage: obj.test_pick_setter() without return types