code: def setUp(self):
      if self.dtype == numpy.float16:
          self.check_forward_options.update(
              {"rtol": 1e-2, "atol": 1e-2}
          )
          self.check_backward_options.update(
              {"rtol": 1e-2, "atol": 1e-2}
          )
          self.check_double_backward_options.update(
              {"rtol": 5e-3, "atol": 5e-2}
          )
      self.skip_double_backward_test = True
  
file_path: chainer/tests/chainer_tests/functions_tests/rnn_tests/test_function_tree_lstm.py
imports: import numpy
  import six
  from chainer import functions
  from chainer import testing
  from chainer.testing import backend
label_desc: Use image node_id 1 for calling the TestTreeLSTM obj's underlying member method code with example usage: obj.setUp() without return types