code: def __init__(
      self,
      fill_value: float = 0.0,
      max_target_dim: int = None,
      align_data: bool = True,
      num_test_dates: int = None,
  ) -> None:
      self.fill_value = fill_value
  
      self.first_timestamp = pd.Timestamp(2200, 1, 1, 12)
      self.last_timestamp = pd.Timestamp(1800, 1, 1, 12)
      self.frequency = None
      self.align_data = align_data
      self.max_target_length = 0
      self.num_test_dates = num_test_dates
      self.max_target_dimension = max_target_dim
  
file_path: gluonts/src/gluonts/nursery/robust-mts-attack/multivariate/datasets/grouper.py
imports: import logging
  import numpy
  import pandas
  from gluonts.dataset.common import ListDataset, DataEntry, Dataset
label_desc: Use image node_id 1 to create a new Grouper object  with example: obj = Grouper(fill_value, max_target_dim, align_data, num_test_dates)