class_docstr: Base class for all other splitter.
code: def training_entry(self, entry: DataEntry) -> DataEntry:
      pass
  
imports: from abc import ABC, abstractmethod
  from dataclasses import dataclass
  from typing import Generator, Optional, Tuple
  import pandas
  from gluonts.dataset import Dataset, DataEntry
  from gluonts.dataset.field_names import FieldName
label_desc: Use image node_id 1 for calling the AbstractBaseSplitter obj's underlying member method code with example usage: obj.training_entry(entry) without return types