docstr: test gelue activation 
docstr_tok: ["test","gelue","activation"]
code: def test_gelu(self):
      """test gelue activation"""
  
      # pylint: disable=invalid-name
      y = utils.gelu(tf.constant([0.5, 0.2], dtype=tf.float32))
      y_true = [0.345714, 0.11585142]
  
      with self.cached_session(use_gpu=False, force_gpu=False) as sess:
          y_pred = sess.run(y)
          self.assertAllClose(y_pred, y_true)
  
file_path: delta/delta/layers/utils_test.py
imports: from absl import logging
  import delta.compat
  from delta.layers import utils
  from delta.layers.utils import cut_or_padding
  from delta.layers.utils import compute_sen_lens
  from delta.layers.utils import compute_doc_lens
  from delta.layers.utils import split_one_doc_to_true_len_sens
label_desc: Use image node_id 3 for calling the LayerUtilsTest obj's underlying member method code with example usage: obj.test_gelu() without return types