code: def test_styler_custom_converter():
      openpyxl = pytest.importorskip("openpyxl")
  
      def custom_converter(css):
          return {"font": {"color": {"rgb": "111222"}}}
  
      df = DataFrame(np.random.default_rng(2).standard_normal((1, 1)))
      styler = df.style.map(lambda x: "color: #888999")
      with tm.ensure_clean(".xlsx") as path:
          with ExcelWriter(path, engine="openpyxl") as writer:
              ExcelFormatter(
                  styler, style_converter=custom_converter
              ).write(writer, sheet_name="custom")
  
          with contextlib.closing(openpyxl.load_workbook(path)) as wb:
              assert (
                  wb["custom"].cell(2, 2).font.color.value == "00111222"
              )
  
file_path: pandas/pandas/tests/io/excel/test_style.py
imports: import contextlib
  import time
  import numpy
  import pytest
  import pandas.util._test_decorators
  from pandas import DataFrame, read_excel
  import pandas._testing
  from pandas.io.excel import ExcelWriter
  from pandas.io.formats.excel import ExcelFormatter
label_desc: Use image node_id 6 for calling a global function with example usage: test_styler_custom_converter() and returns: dict