code: def forward(self, z):
      a = self.mlp(z)
      if self.bias is not None:
          a = a + self.bias
      return torch.sigmoid(a) if self.use_sigmoid else a
  
imports: import torch
  import torch.nn
  from torch.nn.functional import softplus
label_desc: Use image node_id 2 for calling the Decoder obj's underlying member method code with example usage: obj.forward(z) and returns: unknown