code: def _get_freq(ax, series):
      # get frequency from data
      freq = getattr(series.index, "freq", None)
      if freq is None:
          freq = getattr(series.index, "inferred_freq", None)
  
      ax_freq = _get_ax_freq(ax)
  
      # use axes freq if no data freq
      if freq is None:
          freq = ax_freq
  
      # get the period frequency
      if isinstance(freq, DateOffset):
          freq = freq.rule_code
      else:
          freq = get_base_alias(freq)
  
      freq = frequencies.get_period_alias(freq)
      return freq, ax_freq
  
imports: import functools
  from matplotlib import pylab
  import numpy
  from pandas._libs.tslibs.frequencies import FreqGroup, get_base_alias, get_freq, is_subperiod, is_superperiod
  from pandas._libs.tslibs.period import Period
  import pandas.compat
  from pandas.core.dtypes.generic import ABCDatetimeIndex, ABCPeriodIndex, ABCTimedeltaIndex
  from pandas.io.formats.printing import pprint_thing
  from pandas.plotting._converter import TimeSeries_DateFormatter, TimeSeries_DateLocator, TimeSeries_TimedeltaFormatter
  import pandas.tseries.frequencies
  from pandas.tseries.offsets import DateOffset
label_desc: Use image node_id 9 for calling a global function with example usage: _get_freq(ax, series) and returns: freq,  ax_freq