message: added test for failing nested->nested upgrade, resulting in VARCHAR
diff: @@ -406,6 +406,14 @@ class TestResolveObjectColumns(object):
  assert(conversion == reference)
  + def test_mixed_object_types(self):
  + x = pd.DataFrame({
  + 'nested': pd.Series(data=[{'a': 1, 'b': 2}, [5, 4, 3], {'key': [1,2,3], 'value': ['a', 'b', 'c']}], dtype='object'),
  + })
  + res = duckdb.query_df(x, "x", "select * from x").df()
  + assert(res['nested'].dtype == np.dtype('object'))
  +
  +
  def test_numeric_decimal_incompatible(self):
  duckdb_conn = duckdb.connect()
  reference_query = """
  