code: def day_of_month(index: pd.PeriodIndex) -> np.ndarray:
      """
      Day of month encoded as value between [-0.5, 0.5]
      """
  
      # first day of month is `1`, thus we deduct one
      return _normalize(index.day - 1, num=31)
  
imports: from typing import Any, Callable, Dict, List
  import numpy
  import pandas
  from pandas.tseries import offsets
  from pandas.tseries.frequencies import to_offset
  from gluonts.pydantic import BaseModel
label_desc: Use image node_id 10 for calling a global function with example usage: day_of_month(index) and returns: _normalize