code: def test_iat(setup):
      data = pd.DataFrame(
          np.random.rand(10, 5),
          columns=["c" + str(i) for i in range(5)],
          index=["i" + str(i) for i in range(10)],
      )
      df = md.DataFrame(data, chunk_size=3)
  
      with pytest.raises(ValueError):
          _ = df.iat[[1, 2], 3]
  
      result = df.iat[3, 4].execute().fetch()
      assert result == data.iat[3, 4]
  
      result = df.iloc[:, 2].iat[3].execute().fetch()
      assert result == data.iloc[:, 2].iat[3]
  
imports: import os
  import tempfile
  import mars
  import numpy
  import pandas
  import pytest
  from ....None import dataframe
  from ....None import tensor
  from ....utils import pd_release_version
  from ...datasource.read_csv import DataFrameReadCSV
  from ...datasource.read_sql import DataFrameReadSQL
  from ...datasource.read_parquet import DataFrameReadParquet
label_desc: Use image node_id 12 for calling a global function with example usage: test_iat(setup) without return types