class_docstr: `Callback` that handles multiplying the learning rate by `mult_lr` for the critic.
class_docstr_tok: ["`","Callback","`","that","handles","multiplying","the","learning","rate","by","`","mult_lr","`","for","the","critic","."]
docstr: Multiply the current lr if necessary.
docstr_tok: ["Multiply","the","current","lr","if","necessary","."]
code: def before_batch(self):
      "Multiply the current lr if necessary."
      if not self.learn.gan_trainer.gen_mode and self.training:
          self.learn.opt.set_hyper(
              "lr", self.learn.opt.hypers[0]["lr"] * self.mult_lr
          )
  
imports: from __future__ import annotations
  from ..basics import *
  from .all import *
label_desc: Use image node_id 2 for calling the GANDiscriminativeLR obj's underlying member method code with example usage: obj.before_batch() without return types