code: def __init__(self, freq: str) -> None:
      super().__init__()
      # reocurring freq
      freqs = [
          "month",
          "day",
          "hour",
          "minute",
          "weekofyear",
          "weekday",
          "dayofweek",
          "dayofyear",
          "daysinmonth",
      ]
  
      assert freq in freqs
      self.freq = freq
  
file_path: gluonts/src/gluonts/nursery/robust-mts-attack/pts/feature/fourier_date_feature.py
imports: from typing import List
  import numpy
  import pandas
  from pandas.tseries.frequencies import to_offset
  from gluonts.core.component import validated
  from gluonts.time_feature import TimeFeature, norm_freq_str
label_desc: Use image node_id 1 to create a new FourierDateFeatures object from inherited base classes: TimeFeature with example: obj = FourierDateFeatures(freq)