code: def test_plot_month(close_figures):
      dta = elnino.load_pandas().data
      dta["YEAR"] = dta.YEAR.astype(int).apply(str)
      dta = dta.set_index("YEAR").T.unstack()
      dates = pd.to_datetime(
          ["-".join([x[1], x[0]]) for x in dta.index.values],
          format="%b-%Y",
      )
  
      # test dates argument
      fig = month_plot(dta.values, dates=dates, ylabel="el nino")
  
      # test with a TimeSeries DatetimeIndex with no freq
      dta.index = pd.DatetimeIndex(dates)
      fig = month_plot(dta)
  
      # w freq
      dta.index = pd.DatetimeIndex(dates, freq="MS")
      fig = month_plot(dta)
  
      # test with a TimeSeries PeriodIndex
      dta.index = pd.PeriodIndex(dates, freq="M")
      fig = month_plot(dta)
  
      # test localized xlabels
      try:
          with calendar.different_locale("DE_de"):
              fig = month_plot(dta)
              labels = [
                  _.get_text() for _ in fig.axes[0].get_xticklabels()
              ]
              expected = [
                  "Jan",
                  "Feb",
                  ("Mär", "Mrz"),
                  "Apr",
                  "Mai",
                  "Jun",
                  "Jul",
                  "Aug",
                  "Sep",
                  "Okt",
                  "Nov",
                  "Dez",
              ]
              for lbl, exp in zip(labels, expected):
                  if isinstance(exp, tuple):
                      assert lbl in exp
                  else:
                      assert lbl == exp
      except locale.Error:
          pytest.xfail(reason="Failure due to unsupported locale")
  
imports: from statsmodels.compat.pandas import MONTH_END
  from statsmodels.compat.python import lmap
  import calendar
  from io import BytesIO
  import locale
  import numpy
  from numpy.testing import assert_, assert_equal
  import pandas
  import pytest
  from statsmodels.datasets import elnino, macrodata
  from statsmodels.graphics.tsaplots import month_plot, plot_accf_grid, plot_acf, plot_ccf, plot_pacf, plot_predict, quarter_plot, seasonal_plot
  from statsmodels.tsa import arima_process
  from statsmodels.tsa.ar_model import AutoReg
  from statsmodels.tsa.arima.model import ARIMA
label_desc: Use image node_id 10 for calling a global function with example usage: test_plot_month(close_figures) without return types