class_docstr: This class is primarily meant to be instantiated from ``train_test_split()`` function.
class_docstr_tok: ["This","class","is","primarily","meant","to","be","instantiated","from","``","train_test_split","(",")","``","function","."]
code: def _get_horizontal_split_index(self):
      if not self._horizontal_split_index:
          if 0 < self.test_size < 1:
              self._horizontal_split_index = int(
                  len(self.data) * (1 - self.test_size)
              )
          else:
              self._horizontal_split_index = (
                  len(self.data) - self.test_size
              )
  
      return self._horizontal_split_index
  
file_path: darts/darts/utils/model_selection.py
imports: from typing import Optional, Sequence, Tuple, Union
  from darts import TimeSeries
label_desc: Use image node_id 2 for calling the SplitTimeSeriesSequence obj's underlying member method code with example usage: obj._get_horizontal_split_index() and returns: self