class_docstr: Position Encoding module
class_docstr_tok: ["Position","Encoding","module"]
code: def forward(self, pos):
      return th.index_select(self.pe, 1, pos).squeeze(0)
  
file_path: dgl/examples/pytorch/transformer/modules/embedding.py
imports: import numpy
  import torch
  import torch.nn
label_desc: Use image node_id 2 for calling the PositionalEncoding obj's underlying member method code with example usage: obj.forward(pos) and returns: th