code: def test_flatten_in_node(self, histogram_indexer):
      # Test if the flatten in node method returns a new HistogramIndexer with correct parameters
      new_indexer = histogram_indexer.flatten_in_node()
  
      assert new_indexer.node_size == histogram_indexer.node_size
      assert new_indexer.feature_bin_sizes == [
          histogram_indexer.one_node_data_size()
      ]
  
file_path: FATE/python/fate/test/histogram/indexer.py
imports: import pytest
  from fate_utils.histogram import HistogramIndexer, Shuffler
label_desc: Use image node_id 10 for calling the TestHistogramIndexer obj's underlying member method code with example usage: obj.test_flatten_in_node(histogram_indexer) without return types