code: def main(docker_registry, aws, gcp):
      """fiber command line tool that helps to manage workflow of distributed
      fiber applications.
      """
      if docker_registry is not None:
          CONFIG["docker_registry"] = docker_registry
      else:
          CONFIG["docker_registry"] = None
  
      platforms = [aws, gcp]
      platform_names = ["aws", "gcp"]
      n = sum(platforms)
      if n > 1:
          raise ValueError(
              'Only one of "{}" can be set'.format(
                  ", ".join(["--" + p for p in platform_names])
              )
          )
  
      if aws:
          CONFIG["platform"] = "aws"
      elif gcp:
          CONFIG["platform"] = "gcp"
      else:
          CONFIG["platform"] = auto_select_platform()
  
imports: import os
  import json
  import subprocess
  from pathlib import Path
  import click
  import fiber
  import fiber.core
  from fiber.core import ProcessStatus
label_desc: Use image node_id 11 for calling a global function with example usage: main(docker_registry, aws, gcp) without return types