def METHOD_NAME(
    eval_config: config_pb2.EvalConfig, schema: schema_pb2.Schema,
    model_name: str, output_name: str
) -> Tuple[Optional[Union[int, float]], Optional[Union[int, float]]]:
  """Find the min and max value for the label_key for this model / output."""
  model_spec = model_util.get_model_spec(eval_config, model_name)
  if not model_spec:
    return None, None
  label_key = model_util.get_label_key(model_spec, output_name)
  if not label_key:
    return None, None
  label_schema = None
  for feature_schema in schema.feature:
    if feature_schema.name == label_key:
      label_schema = feature_schema
      break
  if label_schema is None:
    return None, None
  # Find the domain
  if label_schema.HasField('int_domain'):
    label_domain = label_schema.int_domain
  elif label_schema.HasField('float_domain'):
    label_domain = label_schema.float_domain
  else:
    return None, None
  left, right = None, None
  if label_domain.HasField('min'):
    left = float(label_domain.min)
  if label_domain.HasField('max'):
    right = float(label_domain.max)
  return left, right