chore: renamed class to avoid name conflict in sphinx

Author: chalmerlowe

packages/bigframes/bigframes/ml/model_selection.py

@@ -21,6 +21,7 @@
 from itertools import chain
 import time
 import typing
+from itertools import chain as _chain
 from typing import Generator, List, Optional, Union
 
 import bigframes_vendored.sklearn.model_selection._split as vendored_model_selection_split
@@ -72,7 +73,7 @@ def train_test_split(
         test_rows = total_rows - train_rows
 
         return list(
-            chain.from_iterable(
+            _chain.from_iterable(
                 [
                     [bf_array.head(train_rows), bf_array.tail(test_rows)]
                     for bf_array in bf_arrays