code: def test_widget_clear_server(self):
      data = {"a": np.arange(0, 50)}
      widget = PerspectiveWidget(data, server=True)
      widget.clear()
      assert widget.table.size() == 0
  
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 23 for calling the TestWidget obj's underlying member method code with example usage: obj.test_widget_clear_server() without return types