code: def _gelu_python(x):
      """
      Original Implementation of the GELU activation function in Google BERT repo when initially created. For
      information: OpenAI GPT's GELU is slightly different (and gives slightly different results): 0.5 * x * (1 +
      torch.tanh(math.sqrt(2 / math.pi) * (x + 0.044715 * torch.pow(x, 3)))) This is now written in C in nn.functional
      Also see the Gaussian Error Linear Units paper: https://arxiv.org/abs/1606.08415
      """
      return x * 0.5 * (1.0 + torch.erf(x / math.sqrt(2.0)))
  
file_path: fastNLP/fastNLP/transformers/torch/activations.py
imports: import math
  from packaging import version
  from fastNLP.envs.imports import _NEED_IMPORT_TORCH
  from fastNLP.core.log import logger
label_desc: Use image node_id 1 for calling a global function with example usage: _gelu_python(x) and returns: unknown