class_docstr: Gaussian Exponential Linear Unit (GELU)
      "Gaussian Error Linear Units (GELUs)", Hendrycks et al, 2016
      https://arxiv.org/abs/1606.08415
  
  Parameters
  ----------
  approximation : string
      Which approximation of GELU calculation to use (erf or tanh).
  
  Inputs:
      - **data**: input tensor with arbitrary shape.
  
  Outputs:
      - **out**: output tensor with the same shape as `data`.
code: def forward(self, x):
      return npx.leaky_relu(x, act_type=self._act_algorithm, name="fwd")
  
imports: from ...None import initializer, npx
  from ..block import HybridBlock
  from ..parameter import Parameter
  from ...util import use_np
label_desc: Use image node_id 2 for calling the GELU obj's underlying member method code with example usage: obj.forward(x) and returns: npx