code: def register_var(self, key, value):
      if hasattr(self, key):
          raise TypeError(
              "Cannot register an already existing parameter '{}'. ".format(
                  key
              )
          )
      object.__setattr__(self, key, value)
  
imports: import inspect
  import json
  import os
  import sys
  import types
  from collections import OrderedDict
  from enum import Enum
  from typing import Dict, List, Union
  from rl_coach.core_types import TrainingSteps, EnvironmentSteps, GradientClippingMethod, RunPhase, SelectedPhaseOnlyDumpFilter, MaxDumpFilter
  from rl_coach.filters.filter import NoInputFilter
  from rl_coach.logger import screen
label_desc: Use image node_id 3 for calling the Parameters obj's underlying member method code with example usage: obj.register_var(key, value) without return types