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(n_splits=5)

for train_index, test_index in tscv.split(X):
   print("TRAIN:", train_index, "TEST:", test_index)
   X_train, X_test = X[train_index], X[test_index]
   y_train, y_test = y[train_index], y[test_index]

>> TRAIN: [0] TEST: [1]
>> TRAIN: [0 1] TEST: [2]
>> TRAIN: [0 1 2] TEST: [3]
>> TRAIN: [0 1 2 3] TEST: [4]
>> TRAIN: [0 1 2 3 4] TEST: [5]