class_docstr: This plan is used for pushing down query string directly to
  backend database engine.
code: def __str__(self):
      return "NativePlan(database_name={}, query_string={})".format(
          self._database_name,
          self._query_string,
      )
  
file_path: evadb/evadb/plan_nodes/native_plan.py
imports: from evadb.plan_nodes.abstract_plan import AbstractPlan
  from evadb.plan_nodes.types import PlanOprType
label_desc: Use image node_id 4 for calling the NativePlan obj's underlying member method code with example usage: obj.__str__() and returns: str