code: def test_update_double_nested_dot(self):
      self.assertEqual(self.layout.updatemenus, ())
  
      # Initialize empty updatemenus
      self.layout["updatemenus"] = [{}, {}]
  
      # Initialize empty buttons in updatemenu[1]
      self.layout["updatemenus.1.buttons"] = [{}, {}, {}]
  
      # Update
      self.layout.update(
          {"updatemenus[1].buttons[2].method": "restyle"}
      )
  
      # Check
      self.assertEqual(
          self.layout["updatemenus[1].buttons[2].method"], "restyle"
      )
      d1, d2 = strip_dict_params(self.layout, self.expected_layout2)
      assert d1 == d2
  
imports: from unittest import TestCase
  import plotly.graph_objs
  from plotly.tests.utils import strip_dict_params
label_desc: Use image node_id 10 for calling the TestAssignCompoundArray obj's underlying member method code with example usage: obj.test_update_double_nested_dot() without return types