code: def test_default_from_params_params(self):
      beam_search = BeamSearch.from_params(
          Params({"beam_size": 2, "end_index": 7})
      )
      assert beam_search.beam_size == 2
      assert beam_search._end_index == 7
  
imports: from typing import Dict, Tuple, Union
  import numpy
  import pytest
  import torch
  from allennlp.common.checks import ConfigurationError
  from allennlp.common.testing import AllenNlpTestCase
  from allennlp.nn.beam_search import MultinomialSampler, BeamSearch, TopKSampler, TopPSampler, GumbelSampler, LengthNormalizedSequenceLogProbabilityScorer, RepeatedNGramBlockingConstraint, StepFunctionTypeWithTimestep, StepFunctionTypeNoTimestep
  from allennlp.common.params import Params
  from allennlp.nn.util import min_value_of_dtype
label_desc: Use image node_id 16 for calling the BeamSearchTest obj's underlying member method code with example usage: obj.test_default_from_params_params() without return types