code: def _datetime_frequency_rank():
      column_names = ["date_order", "frequency", "rank"]
      date_order = [
          ["year", "Y", 0],
          ["quarter", "Q", 1],
          ["month", "M", 2],
          ["week", "W", 3],
          ["day", "D", 4],
          ["hour", "H", 5],
      ]
      datetime_freq = pd.DataFrame(date_order, columns=column_names)
      return datetime_freq
  
file_path: sktime/sktime/transformations/series/peak.py
imports: import pandas
  from sktime.transformations.base import BaseTransformer
label_desc: Use image node_id 1 for calling a global function with example usage: _datetime_frequency_rank() and returns: datetime_freq