code: def plot_lr_fun():
      """Visualizes lr function."""
      epochs = list(range(cfg.OPTIM.MAX_EPOCH))
      lrs = [get_epoch_lr(epoch) for epoch in epochs]
      plt.plot(epochs, lrs, ".-")
      plt.title("lr_policy: {}".format(cfg.OPTIM.LR_POLICY))
      plt.xlabel("epochs")
      plt.ylabel("learning rate")
      plt.ylim(bottom=0)
      plt.show()
  
file_path: pycls/pycls/core/optimizer.py
imports: import matplotlib.pyplot
  import numpy
  import torch
  from pycls.core.config import cfg
label_desc: Use image node_id 9 for calling a global function with example usage: plot_lr_fun() without return types