code: def test_query_cache_key_does_not_change_for_non_existent_or_null(
      self,
  ):
      self.login(username="admin")
      payload = get_query_context(
          "birth_names", add_postprocessing_operations=True
      )
      del payload["queries"][0]["granularity"]
  
      # construct baseline query_cache_key from query_context with post processing operation
      query_context: QueryContext = ChartDataQueryContextSchema().load(
          payload
      )
      query_object: QueryObject = query_context.queries[0]
      cache_key_original = query_context.query_cache_key(query_object)
  
      payload["queries"][0]["granularity"] = None
      query_context = ChartDataQueryContextSchema().load(payload)
      query_object = query_context.queries[0]
  
      assert (
          query_context.query_cache_key(query_object)
          == cache_key_original
      )
  
imports: import re
  import time
  from typing import Any
  import numpy
  import pandas
  import pytest
  from pandas import DateOffset
  from superset import db
  from superset.charts.schemas import ChartDataQueryContextSchema
  from superset.common.chart_data import ChartDataResultFormat, ChartDataResultType
  from superset.common.query_context import QueryContext
  from superset.common.query_context_factory import QueryContextFactory
  from superset.common.query_object import QueryObject
  from superset.connectors.sqla.models import SqlMetric
  from superset.daos.datasource import DatasourceDAO
  from superset.extensions import cache_manager
  from superset.superset_typing import AdhocColumn
  from superset.utils.core import AdhocMetricExpressionType, backend, DatasourceType, QueryStatus
  from superset.utils.pandas_postprocessing.utils import FLAT_COLUMN_SEPARATOR
  from tests.integration_tests.base_tests import SupersetTestCase
  from tests.integration_tests.conftest import only_postgresql, only_sqlite
  from tests.integration_tests.fixtures.birth_names_dashboard import load_birth_names_dashboard_with_slices, load_birth_names_data
  from tests.integration_tests.fixtures.query_context import get_query_context
label_desc: Use image node_id 5 for calling the TestQueryContext obj's underlying member method code with example usage: obj.test_query_cache_key_does_not_change_for_non_existent_or_null() without return types