code: def __init__(self, deco, func):
      msg = (
          "Step '{step}' already has a decorator '{deco}'. "
          "You can specify this decorator only once.".format(
              step=func.__name__, deco=deco
          )
      )
      super(DuplicateStepDecoratorException, self).__init__(msg)
  
imports: from functools import partial
  import json
  import re
  import os
  import sys
  from .flowspec import FlowSpec
  from .exception import MetaflowInternalError, MetaflowException, InvalidDecoratorAttribute
  from metaflow._vendor import click
label_desc: Use image node_id 1 to create a new DuplicateStepDecoratorException object from inherited base classes: MetaflowException with example: obj = DuplicateStepDecoratorException(deco, func)