code: def test_widget_load_table_indexed(self):
      table = Table({"a": np.arange(0, 50)}, index="a")
      widget = PerspectiveWidget(table, plugin="X Bar")
      assert widget.plugin == "X Bar"
      load_msg = widget._make_load_message()
      assert load_msg.to_dict() == {
          "id": -2,
          "type": "table",
          "data": {
              "table_name": widget.table_name,
              "options": {"index": "a"},
          },
      }
  
imports: from datetime import date, datetime
  from functools import partial
  from types import MethodType
  import numpy
  from perspective import PerspectiveError, PerspectiveWidget, Table
  from pytest import raises
label_desc: Use image node_id 14 for calling the TestWidget obj's underlying member method code with example usage: obj.test_widget_load_table_indexed() without return types