code: def test_widget_delete(self):
      data = {"a": np.arange(0, 50)}
      widget = PerspectiveWidget(data)
      mocked_post = partial(mock_post, assert_msg={"cmd": "delete"})
      widget.post = MethodType(mocked_post, widget)
      widget.delete()
      assert widget.table is None
  
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 26 for calling the TestWidget obj's underlying member method code with example usage: obj.test_widget_delete() without return types