code: def forward(self, x):
      with torch.no_grad():
          x = x * math.sqrt(self.d_model)
          seq_len = x.size(0)
          pe = self.pe[:, :seq_len].view(seq_len, 1, self.d_model)
          x = x + pe
          return x
  
imports: import math
  from typing import Dict, List, Tuple, Union
  import torch
  import torch.nn
  import torch.nn.functional
label_desc: Use image node_id 2 for calling the PositionalEncoder obj's underlying member method code with example usage: obj.forward(x) and returns: x