code: def require_env(name):
      if name not in os.environ:
          raise remotelib.OperationError(
              f"missing required {name} environment variable"
          )
  
imports: import logging
  import os
  import subprocess
  import sys
  from guild import config
  from guild import file_util
  from guild import log
  from guild import remote
  from guild import util
  from guild import var
label_desc: Use image node_id 1 for calling a global function with example usage: require_env(name) without return types