class_docstr: Compose Learning Rate Schedulers
  
  Parameters
  ----------
  
  schedulers: list
      list of LRScheduler objects
class_docstr_tok: ["Compose","Learning","Rate","Schedulers","Parameters","--","--","--","--","--","schedulers",":","list","list","of","LRScheduler","objects"]
code: def __call__(self, num_update):
      self.update(num_update)
      return self.learning_rate
  
file_path: gluon-cv/gluoncv/utils/lr_scheduler.py
imports: from __future__ import division
  import warnings
  from math import pi, cos
  from mxnet import lr_scheduler
label_desc: Use image node_id 3 for calling the LRSequential obj's underlying member method code with example usage: obj.__call__(num_update) and returns: self