class_docstr: CTC-based loss for S2ST.
code: def forward(loss):
      # dummy forward
      return loss
  
imports: import torch
  import torch.nn.functional
  from typeguard import check_argument_types
  from espnet2.s2st.losses.abs_loss import AbsS2STLoss
label_desc: Use image node_id 2 for calling the S2STCTCLoss obj's underlying member method code with example usage: obj.forward(loss) and returns: loss