code: def test_process_form_extras_updates_sensitive_placeholder_unchanged(
      mock_base_hook, mock_pm_hooks, mock_import_str
  ):
      """
      Test the handling of sensitive unchanged field (where placeholder has not been modified).
      """
  
      # Testing parameters set in both extra and custom fields (connection updates).
      mock_form = mock.Mock()
      mock_form.data = {
          "conn_type": "test4",
          "conn_id": "extras_test4",
          "extra": '{"sensitive_extra": "RATHER_LONG_SENSITIVE_FIELD_PLACEHOLDER", "extra__custom": "value"}',
      }
      mock_base_hook.get_connection.return_value = Connection(
          extra='{"sensitive_extra": "old_value"}'
      )
      cmv = ConnectionModelView()
      cmv._iter_extra_field_names_and_sensitivity = mock.Mock(
          return_value=[
              ("sensitive_extra_key", "sensitive_extra", True)
          ]
      )
      cmv.process_form(form=mock_form, is_created=True)
  
      assert json.loads(mock_form.extra.data) == {
          "extra__custom": "value",
          "sensitive_extra": "old_value",
      }
  
imports: from __future__ import annotations
  import json
  from typing import Any
  from unittest import mock
  from unittest.mock import PropertyMock
  import pytest
  from airflow.models import Connection
  from airflow.utils.session import create_session
  from airflow.www.views import ConnectionFormWidget, ConnectionModelView
  from tests.test_utils.www import _check_last_log, _check_last_log_masked_connection, check_content_in_response
label_desc: Use image node_id 15 for calling a global function with example usage: test_process_form_extras_updates_sensitive_placeholder_unchanged(mock_base_hook, mock_pm_hooks, mock_import_str) without return types