code: def test_left_merge_na_buglet(self):
      left = DataFrame(
          {
              "id": list("abcde"),
              "v1": np.random.default_rng(2).standard_normal(5),
              "v2": np.random.default_rng(2).standard_normal(5),
              "dummy": list("abcde"),
              "v3": np.random.default_rng(2).standard_normal(5),
          },
          columns=["id", "v1", "v2", "dummy", "v3"],
      )
      right = DataFrame(
          {
              "id": ["a", "b", np.nan, np.nan, np.nan],
              "sv3": [1.234, 5.678, np.nan, np.nan, np.nan],
          }
      )
  
      result = merge(left, right, on="id", how="left")
  
      rdf = right.drop(["id"], axis=1)
      expected = left.join(rdf)
      tm.assert_frame_equal(result, expected)
  
imports: import numpy
  import pytest
  import pandas.util._test_decorators
  import pandas
  from pandas import DataFrame, Index, MultiIndex, RangeIndex, Series, Timestamp, option_context
  import pandas._testing
  from pandas.core.reshape.concat import concat
  from pandas.core.reshape.merge import merge
label_desc: Use image node_id 9 for calling the TestMergeMulti obj's underlying member method code with example usage: obj.test_left_merge_na_buglet() without return types