def corofunc1():
            called[0] += 1
            return event.ReturnValue(insert_events=[evt2], append_events=[evt])
def test_impl():
            A = StringArray(['ABC', 'BB', 'ADEF'])
            df = pd.DataFrame({'A': A})
            B = df.A.str.contains('AB*', regex=True)
            return B.sum()