code: def test_boxplot_type_coercion():
      df = names_df
      df["cars"] = df["cars"].astype(str)
      df = boxplot(
          df=df,
          groupby=["region"],
          whisker_type=PostProcessingBoxplotWhiskerType.TUKEY,
          metrics=["cars"],
      )
  
      columns = {column for column in df.columns}
      assert columns == {
          "cars__mean",
          "cars__median",
          "cars__q1",
          "cars__q3",
          "cars__max",
          "cars__min",
          "cars__count",
          "cars__outliers",
          "region",
      }
      assert len(df) == 4
  
file_path: superset/tests/unit_tests/pandas_postprocessing/test_boxplot.py
imports: import pytest
  from superset.exceptions import InvalidPostProcessingError
  from superset.utils.core import PostProcessingBoxplotWhiskerType
  from superset.utils.pandas_postprocessing import boxplot
  from tests.unit_tests.fixtures.dataframes import names_df
label_desc: Use image node_id 5 for calling a global function with example usage: test_boxplot_type_coercion() without return types