code: def get_trainer_rank():
      """Get the rank of the current trainer process.
  
      This function can only be called in the trainer process. It will result in
      an error if it's called in the process of other roles.
      """
      assert CUR_ROLE == "default"
      if IS_STANDALONE:
          return 0
      else:
          return PER_ROLE_RANK["default"][rpc.get_rank()]
  
imports: import os
  import numpy
  from .None import rpc
label_desc: Use image node_id 4 for calling a global function with example usage: get_trainer_rank() and returns: int, PER_ROLE_RANK