class_docstr: Transformer encoder
  Encoder encoder contains a list of EncoderLayer, and a LayerNorm.
  Attributes:
      layers: nn.LayerList contains multiple EncoderLayers
      encoder_norm: nn.LayerNorm which is applied after last encoder layer
code: def forward(self, x):
      for layer in self.layers:
          x = layer(x)
      out = self.encoder_norm(x)
      return out
  
imports: import copy
  import paddle
  import paddle.nn
  from disco_diffusion_ernievil_base.vit_b_16x.ernievil2.transformers.droppath import DropPath
label_desc: Use image node_id 3 for calling the Encoder obj's underlying member method code with example usage: obj.forward(x) and returns: out