code: def test_valid_actions_unconstrained(self):
      self.parser.constraints_intent_slot_nesting = False
      self.parser.constraints_no_slots_inside_unsupported = False
      state = self.populate_buffer()
  
      # Valid Actions at beginning: all nonterminals
      self.check_valid_actions(state, self.parser.valid_NT_idxs)
  
      # After pushing IN:A: all nonterminals, SHIFT
      self.parser.push_action(
          state, self.parser.actions_vocab.stoi["IN:A"]
      )
      self.check_valid_actions(
          state, self.parser.valid_NT_idxs + [self.parser.shift_idx]
      )
  
      # After pushing SL:C and SHIFT: all nonterminals, SHIFT, REDUCE
      self.parser.push_action(
          state, self.parser.actions_vocab.stoi["SL:C"]
      )
      self.parser.push_action(
          state, self.parser.actions_vocab.stoi["SHIFT"]
      )
      self.check_valid_actions(
          state,
          self.parser.valid_NT_idxs
          + [self.parser.shift_idx]
          + [self.parser.reduce_idx],
      )
  
      # After all SHIFTs: only REDUCE
      self.parser.push_action(
          state, self.parser.actions_vocab.stoi["SHIFT"]
      )
      self.check_valid_actions(state, [self.parser.reduce_idx])
  
      # After all REDUCEs, no valid actions
      self.parser.push_action(
          state, self.parser.actions_vocab.stoi["REDUCE"]
      )
      self.parser.push_action(
          state, self.parser.actions_vocab.stoi["REDUCE"]
      )
      self.check_valid_actions(state, [])
  
imports: import unittest
  from collections import Counter
  import torch
  import torch.nn
  from pytext.common.constants import Stage
  from pytext.config.module_config import PoolingType
  from pytext.legacy.vocab import Vocab
  from pytext.models.embeddings import DictEmbedding, EmbeddingList, WordEmbedding
  from pytext.models.semantic_parsers.rnng.rnng_data_structures import CompositionalNN, CompositionalSummationNN, Element, ParserState, StackLSTM
  from pytext.models.semantic_parsers.rnng.rnng_parser import RNNGParser
label_desc: Use image node_id 4 for calling the RNNGParserTest obj's underlying member method code with example usage: obj.test_valid_actions_unconstrained() without return types