class_docstr: Helper class to avoid loading two dataset columns into memory when accessing it.
code: def __getitem__(self, i):
      return {
          self.first_key: self.dataset[i][self.first_col],
          self.second_key: self.dataset[i][self.second_col]
          if self.second_col
          else None,
      }
  
file_path: evaluate/src/evaluate/evaluator/utils.py
imports: from datasets import Dataset, get_dataset_split_names
label_desc: Use image node_id 3 for calling the DatasetColumnPair obj's underlying member method code with example usage: obj.__getitem__(i) and returns: dict