class_docstr: Scheduler that decays linearly.
code: def train_step(self, scheduler_steps):
      if scheduler_steps >= self.max_lr_steps:
          raise StopTrainException("End of Linear LR Schedule")
      self.scheduler.step()
  
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 3 for calling the LinearLRScheduler obj's underlying member method code with example usage: obj.train_step(scheduler_steps) without return types