class_docstr: Not sure if I can avoid the state machine here
class_docstr_tok: ["Not","sure","if","I","can","avoid","the","state","machine","here"]
code: def _get_wom_rule(self):
      #         wdiffs = unique(np.diff(self.index.week))
      # We also need -47, -49, -48 to catch index spanning year boundary
      #     if not lib.ismember(wdiffs, set([4, 5, -47, -49, -48])).all():
      #         return None
  
      weekdays = unique(self.index.weekday)
      if len(weekdays) > 1:
          return None
  
      week_of_months = unique((self.index.day - 1) // 7)
      # Only attempt to infer up to WOM-4. See #9425
      week_of_months = week_of_months[week_of_months < 4]
      if len(week_of_months) == 0 or len(week_of_months) > 1:
          return None
  
      # get which week
      week = week_of_months[0] + 1
      wd = int_to_weekday[weekdays[0]]
  
      return "WOM-{week}{weekday}".format(week=week, weekday=wd)
  
imports: from datetime import timedelta
  import re
  import numpy
  from pytz import AmbiguousTimeError
  from pandas._libs.algos import unique_deltas
  from pandas._libs.tslibs import Timedelta, Timestamp
  from pandas._libs.tslibs.ccalendar import MONTH_ALIASES, int_to_weekday
  from pandas._libs.tslibs.conversion import tz_convert
  from pandas._libs.tslibs.fields import build_field_sarray
  import pandas._libs.tslibs.frequencies
  from pandas._libs.tslibs.offsets import _offset_to_period_map
  import pandas._libs.tslibs.resolution
  from pandas._libs.tslibs.resolution import Resolution
  from pandas._libs.tslibs.timezones import UTC
  import pandas.compat
  from pandas.compat import zip
  from pandas.util._decorators import cache_readonly
  from pandas.core.dtypes.common import is_datetime64_dtype, is_period_arraylike, is_timedelta64_dtype
  from pandas.core.dtypes.generic import ABCSeries
  from pandas.core.algorithms import unique
  from pandas.tseries.offsets import DateOffset, Day, Hour, Micro, Milli, Minute, Nano, Second, prefix_mapping
label_desc: Use image node_id 19 for calling the _FrequencyInferer obj's underlying member method code with example usage: obj._get_wom_rule() and returns: str, None, None