class_docstr: A custom iterator for loading files in batches.
code: def load_file(self) -> Tuple[np.ndarray, np.ndarray]:
      X_path, y_path = self._file_paths[self._it]
      X = np.load(X_path)
      y = np.load(y_path)
      assert X.shape[0] == y.shape[0]
      return X, y
  
file_path: xgboost/demo/guide-python/external_memory.py
imports: import os
  import tempfile
  from typing import Callable, List, Tuple
  import numpy
  from sklearn.datasets import make_regression
  import xgboost
label_desc: Use image node_id 2 for calling the Iterator obj's underlying member method code with example usage: obj.load_file() and returns: X,  y