code: def get_hostname(config_url=None):
      
      region_string = ""
      if config_url:
          return urlparse(config_url).hostname
      aws_region = os.getenv("AWS_REGION")
      if aws_region and aws_region in SUPPORTED_REGIONS:
          region_string = ".%s" % aws_region
      return "metrics-api%s.iopipe.com" % region_string
docs: Returns the IOpipe collector's hostname. If  the `AWS_REGION` environment
      variable is not set or unsupported then `us-east-1` will be used by
      default. In this case, `us-east-1` is `metrics-api.iopipe.com`.
  
      :param config_url: A optional config URL to use.
      :returns: The collector's hostname.
      :rtype: str