import numpy as np
from sklearn.model_selection import TimeSeriesSplit

X = np.array([[1, 2], [3, 4], [1, 2], [3, 4], [1, 2], [3, 4]])
y = np.array([1, 2, 3, 4, 5, 6])

tscv = TimeSeriesSplit()

for i, (train_index, test_index) in enumerate(tscv.split(X)):
    print(f"Fold {i}:")
    print(f"  Train: index={train_index}")
    print(f"  Test:  index={test_index}")

"""
Fold 0:
  Train: index=[0]
  Test:  index=[1]
Fold 1:
  Train: index=[0 1]
  Test:  index=[2]
Fold 2:
  Train: index=[0 1 2]
  Test:  index=[3]
Fold 3:
  Train: index=[0 1 2 3]
  Test:  index=[4]
Fold 4:
  Train: index=[0 1 2 3 4]
  Test:  index=[5]
"""