code: def _get_freq(ax: Axes, series: Series):
      # get frequency from data
      freq = getattr(series.index, "freq", None)
      if freq is None:
          freq = getattr(series.index, "inferred_freq", None)
          freq = to_offset(freq)
  
      ax_freq = _get_ax_freq(ax)
  
      # use axes freq if no data freq
      if freq is None:
          freq = ax_freq
  
      # get the period frequency
      freq = _get_period_alias(freq)
      return freq, ax_freq
  
imports: from __future__ import annotations
  from datetime import timedelta
  import functools
  from typing import TYPE_CHECKING, cast
  import numpy
  from pandas._libs.tslibs import BaseOffset, Period, to_offset
  from pandas._libs.tslibs.dtypes import FreqGroup
  from pandas.core.dtypes.generic import ABCDatetimeIndex, ABCPeriodIndex, ABCTimedeltaIndex
  from pandas.io.formats.printing import pprint_thing
  from pandas.plotting._matplotlib.converter import TimeSeries_DateFormatter, TimeSeries_DateLocator, TimeSeries_TimedeltaFormatter
  from pandas.tseries.frequencies import get_period_alias, is_subperiod, is_superperiod
label_desc: Use image node_id 9 for calling a global function with example usage: _get_freq(ax, series) and returns: freq,  ax_freq