class_docstr: ```
  Abstract class used to tune and train Keras models. The fit method is
  an abstract method and must be implemented by subclasses.
  ```
class_docstr_tok: ["``","`","Abstract","class","used","to","tune","and","train","Keras","models",".","The","fit","method","is","an","abstract","method","and","must","be","implemented","by","subclasses",".","``","`"]
code: def _cb_sgdr(
      self,
      max_lr,
      steps_per_epoch,
      cycle_len,
      cycle_mult,
      lr_decay=1.0,
      callbacks=[],
  ):
      if callbacks and "SGDRScheduler" in [
          type(cb).__name__ for cb in callbacks
      ]:
          return callbacks
      # configuration
      min_lr = 1e-9
      if max_lr <= min_lr:
          min_lr = max_lr / 10
  
      #  use learning_rate schedule
      if cycle_len is not None:
          if not isinstance(callbacks, list):
              callbacks = []
          from .lroptimize.sgdr import SGDRScheduler
  
          schedule = SGDRScheduler(
              min_lr=min_lr,
              max_lr=max_lr,
              steps_per_epoch=steps_per_epoch,
              lr_decay=lr_decay,
              cycle_length=cycle_len,
              mult_factor=cycle_mult,
          )
          callbacks.append(schedule)
      if not callbacks:
          callbacks = None
      return callbacks
  
imports: from .None import utils
  from .graph.predictor import LinkPredictor, NodePredictor
  from .graph.preprocessor import LinkPreprocessor, NodePreprocessor
  from .imports import *
  from .lroptimize.lrfinder import *
  from .tabular.predictor import TabularPredictor
  from .tabular.preprocessor import TabularPreprocessor
  from .text.ner.predictor import NERPredictor
  from .text.ner.preprocessor import NERPreprocessor
  from .text.predictor import TextPredictor
  from .text.preprocessor import BERTPreprocessor, TextPreprocessor, TransformersPreprocessor
  from .vision.predictor import ImagePredictor
  from .vision.preprocessor import ImagePreprocessor
label_desc: Use image node_id 27 for calling the Learner obj's underlying member method code with example usage: obj._cb_sgdr(max_lr, steps_per_epoch, cycle_len, cycle_mult, lr_decay, callbacks) and returns: callbacks, callbacks