class_docstr: GRU that can handle zero-length sequences
code: def handle_no_encoding(
      self,
      hidden_state: HiddenState,
      no_encoding: torch.BoolTensor,
      initial_hidden_state: HiddenState,
  ) -> HiddenState:
      return hidden_state.masked_scatter(
          no_encoding, initial_hidden_state
      )
  
imports: from abc import ABC, abstractmethod
  from typing import Tuple, Type, Union
  import torch
  from torch import nn
  from torch.nn.utils import rnn
label_desc: Use image node_id 1 for calling the GRU obj's underlying member method code with example usage: obj.handle_no_encoding(hidden_state, no_encoding, initial_hidden_state) and returns: hidden_state