code: def test_check_y_returns_series():
      s = pd.Series([0, 1, 2, 3, 4])
      assert_series_equal(check_y(s), s)
  
imports: import numpy
  import pandas
  import pytest
  from pandas.testing import assert_frame_equal, assert_series_equal
  from scipy.sparse import csr_matrix
  from feature_engine.dataframe_checks import _check_contains_inf, _check_contains_na, _check_X_matches_training_df, check_X, check_X_y, check_y
label_desc: Use image node_id 5 for calling a global function with example usage: test_check_y_returns_series() without return types