code: def test_summary_method(valid_cv):
      cv_summary = valid_cv.summary()
      assert (
          isinstance(cv_summary, pd.DataFrame) and not cv_summary.empty
      ), f"{type(cv_summary)}\n{cv_summary}"
  
imports: import numpy
  import pandas
  import pytest
  from sklearn.linear_model import Lasso
  from sklearn.model_selection import GridSearchCV
  from sklearn.pipeline import Pipeline
  from sklego.model_selection import GroupTimeSeriesSplit
label_desc: Use image node_id 7 for calling a global function with example usage: test_summary_method(valid_cv) without return types