class_docstr: Scheduler that decays by a fixed multiplicative rate at each valid step.
code: def __init__(
      self, optimizer, patience, decay, warmup_updates, warmup_rate
  ):
      super().__init__(warmup_updates, warmup_rate)
      self.scheduler = optim.lr_scheduler.StepLR(
          optimizer, patience, gamma=decay
      )
  
imports: import math
  from typing import Optional
  from parlai.core.params import ParlaiParser
  from parlai.core.opt import Opt
  from abc import abstractmethod
  from torch import optim
  import numpy
  from parlai.core.exceptions import StopTrainException
  from parlai.utils.misc import warn_once
label_desc: Use image node_id 1 to create a new FixedLRScheduler object from inherited base classes: ParlAILRScheduler with example: obj = FixedLRScheduler(optimizer, patience, decay, warmup_updates, warmup_rate)