code: def ts_inverse_transform(
      series: TimeSeries, params: Mapping[str, Mapping[str, MapperFn]]
  ) -> TimeSeries:
      return series.map(params["fixed"]["_inverse_fn"])
  
file_path: darts/darts/dataprocessing/transformers/mappers.py
imports: from typing import Any, Callable, Mapping, Union
  import numpy
  import pandas
  from darts.logging import get_logger
  from darts.timeseries import TimeSeries
  from .base_data_transformer import BaseDataTransformer
  from .invertible_data_transformer import InvertibleDataTransformer
label_desc: Use image node_id 3 for calling the InvertibleMapper obj's underlying member method code with example usage: obj.ts_inverse_transform(series, params) and returns: series