code: def create_instance(self, str_tokens: List[str]):
      tokens = [Token(t) for t in str_tokens]
      instance = Instance(
          {"text": TextField(tokens, self.token_indexers)}
      )
      instance.index_fields(self.vocab)
      return instance
  
file_path: allennlp/tests/data/samplers/sampler_test.py
imports: from typing import List, Iterable, Dict, Union
  from allennlp.common.testing import AllenNlpTestCase
  from allennlp.data import Vocabulary, Instance, Token, Batch, DatasetReader
  from allennlp.data.fields import TextField
  from allennlp.data.token_indexers import SingleIdTokenIndexer
label_desc: Use image node_id 3 for calling the SamplerTest obj's underlying member method code with example usage: obj.create_instance(str_tokens) and returns: instance