code: def setup(self):
      self._execution_context = MagicMock(name="ExecutionContext")
      self._manager = QueryPacksManager(self._execution_context)
  
imports: from datetime import datetime, timezone
  from mock import MagicMock, patch
  from nose.tools import assert_equals, assert_false, assert_true
  from streamalert.scheduled_queries.query_packs.manager import QueryPack, QueryPacksManager, QueryPackExecutionContext, QueryPacksManagerFactory
  from streamalert.scheduled_queries.query_packs.parameters import QueryParameterGenerator
label_desc: Use image node_id 2 for calling the TestQueryPacksManager obj's underlying member method code with example usage: obj.setup() without return types