docs: def execute_as(collector):
      """Execute a command (after the --) as an assumed role (specified by --artifact)"""
      # Gonna assume role anyway...
      collector.configuration['amazon']._validated = True
  
      # Find the arn we want to assume
      account_id = collector.configuration['accounts'][collector.configuration['aws_syncr'].environment]
      arn = "arn:aws:iam::{0}:role/{1}".format(account_id, collector.configuration['aws_syncr'].artifact)
  
      # Determine the command to run
      parts = shlex.split(collector.configuration["aws_syncr"].extra)
      if not parts:
          suggestion = " ".join(sys.argv) + " -- /path/to/command_to_run"
          msg = "No command was provided. Try something like:\n\t\t{0}".format(suggestion)
          raise AwsSyncrError(msg)
  
      # Get our aws credentials environment variables from the assumed role
      env = dict(os.environ)
      env.update(collector.configuration['amazon'].iam.assume_role_credentials(arn))
  
      # Turn into the command we want to execute
      os.execvpe(parts[0], parts, env)