code: def test_widget_load_pivot_table(self, superstore):
      pivot_table = pd.pivot_table(
          superstore,
          values="Discount",
          index=["Country", "Region"],
          columns=["Category", "Segment"],
      )
      widget = PerspectiveWidget(pivot_table)
      assert widget.group_by == ["Country", "Region"]
      assert widget.split_by == ["Category", "Segment"]
      assert widget.columns == ["value"]
      # table should host flattened data
      view = widget.table.view()
      assert view.num_rows() == 60
      assert view.num_columns() == 6
  
file_path: perspective/python/perspective/perspective/tests/widget/test_widget_pandas.py
imports: from datetime import date
  import pandas
  import numpy
  from perspective import Table, PerspectiveWidget
label_desc: Use image node_id 4 for calling the TestWidgetPandas obj's underlying member method code with example usage: obj.test_widget_load_pivot_table(superstore) without return types