code: def cosine_decay(learning_rate, global_step, decay_steps, alpha=0.0):
      global_step = min(global_step, decay_steps)
      cosine_decay = 0.5 * (
          1 + math.cos(math.pi * global_step / decay_steps)
      )
      decayed = (1 - alpha) * cosine_decay + alpha
      return learning_rate * decayed
  
imports: import argparse
  import os
  import math
  import matplotlib.pyplot
  import torch
  import torch.nn
  from torchdiffeq import odeint, odeint_event
  from bouncing_ball import BouncingBallExample
label_desc: Use image node_id 2 for calling a global function with example usage: cosine_decay(learning_rate, global_step, decay_steps, alpha) and returns: unknown