code: def gelu(input_tensor):
      """Gaussian Error Linear Unit.
  
      This is a smoother version of the RELU.
      Original paper: https://arxiv.org/abs/1606.08415
  
      Args:
        input_tensor: float Tensor to perform activation.
  
      Returns:
        `input_tensor` with the GELU activation applied.
      """
      cdf = 0.5 * (1.0 + tf.erf(input_tensor / tf.sqrt(2.0)))
      return input_tensor * cdf
  
imports: import copy
  import tensorflow
  import tensorflow.contrib.rnn
  from texar.tf.hyperparams import HParams
  from texar.tf.utils import utils
  from texar.tf.utils.dtypes import is_str
  from texar.tf.utils.variables import add_variable
  from texar.tf.utils.mode import is_train_mode, switch_dropout
label_desc: Use image node_id 30 for calling a global function with example usage: gelu(input_tensor) and returns: unknown