code: def forward(self, xs, ys=None, cands=None):
      xs_enc = []
      ys_enc = []
      xs_emb = self.encoder(xs)
      if self.lins > 0:
          xs_emb = self.lin(xs_emb)
      if ys is not None:
          # training includes the correct example first.
          xs_enc.append(xs_emb)
          ys_enc.append(self.encoder2(ys))
      for c in cands:
          xs_enc.append(xs_emb)
          c_emb = self.encoder2(c)
          ys_enc.append(c_emb)
      return torch.cat(xs_enc), torch.cat(ys_enc)
  
file_path: ParlAI/parlai/agents/starspace/modules.py
imports: import math
  import torch
  import torch.nn
label_desc: Use image node_id 2 for calling the Starspace obj's underlying member method code with example usage: obj.forward(xs, ys, cands) and returns: torch,  torch