code: def min_train_series_length(self) -> int:
      if (
          isinstance(self.seasonal_periods, List)
          and len(self.seasonal_periods) > 0
          and max(self.seasonal_periods) > 1
      ):
          return 2 * max(self.seasonal_periods)
      return 3
  
imports: from abc import ABC, abstractmethod
  from typing import List, Optional, Tuple, Union
  import numpy
  from scipy.special import inv_boxcox
  from tbats import BATS
  from tbats import TBATS
  from darts.logging import get_logger
  from darts.models.forecasting.forecasting_model import LocalForecastingModel
  from darts.timeseries import TimeSeries
label_desc: Use image node_id 7 for calling the _BaseBatsTbatsModel obj's underlying member method code with example usage: obj.min_train_series_length() and returns: int, unknown