code: def rsqrt_decay(step, warmup_steps):
      """Decay based on the reciprocal of the step square root."""
      return 1.0 / sqrt(max(step, warmup_steps))
  
imports: import torch
  import torch.optim
  from torch.nn.utils import clip_grad_norm_
  import operator
  import functools
  from copy import copy
  from math import sqrt
  import types
  import os
  import importlib
  from onmt.utils.misc import fn_args
label_desc: Use image node_id 6 for calling a global function with example usage: rsqrt_decay(step, warmup_steps) and returns: unknown