class_docstr: Base class for model validator. All validator should subclass from this so that
  they can be registered in the workflows.
docstr: This method takes RLTrainingOutput so that it can extract anything it
  might need from it.
code: def do_validate(
      self,
      training_output: RLTrainingOutput,
      result_history: Optional[List[RLTrainingOutput]] = None,
      input_table_spec: Optional[TableSpec] = None,
  ) -> ValidationResult:
      """
      This method takes RLTrainingOutput so that it can extract anything it
      might need from it.
      """
      pass
  
file_path: ReAgent/reagent/validators/model_validator.py
imports: import abc
  import inspect
  import logging
  from typing import List, Optional
  from reagent.core.registry_meta import RegistryMeta
  from reagent.core.result_registries import ValidationResult
  from reagent.workflow.types import RLTrainingOutput, TableSpec
label_desc: Use image node_id 2 for calling the ModelValidator obj's underlying member method code with example usage: obj.do_validate(training_output, result_history, input_table_spec) without return types