code: def _plot_series(series, ax=None, **kwargs):
      if isinstance(series, tuple):
          return plot_series(*series, ax=ax, **kwargs)
      else:
          return plot_series(series, ax=ax, **kwargs)
  
imports: import re
  import numpy
  import pandas
  import pytest
  from sktime.datasets import load_airline
  from sktime.tests.test_switch import run_test_for_class
  from sktime.utils.plotting import plot_correlations, plot_lags, plot_series
  from sktime.utils.validation._dependencies import _check_soft_dependencies
  from sktime.utils.validation.series import VALID_DATA_TYPES
label_desc: Use image node_id 1 for calling a global function with example usage: _plot_series(series, ax) and returns: plot_series, plot_series