class_docstr: Output for a callback step.
  
  Attributes:
      output_name (str): The output name
      output_type (CallbackOutputTypeEnum): The output type
class_docstr_tok: ["Output","for","a","callback","step",".","Attributes",":","output_name","(","str",")",":","The","output","name","output_type","(","CallbackOutputTypeEnum",")",":","The","output","type"]
docstr: An internal classmethod for the 'Get' expression dict for a `CallbackOutput`.
  
  Args:
      name (str): The name of the callback output.
      step_name (str): The name of the step the callback step associated
          with this output belongs to.
docstr_tok: ["An","internal","classmethod","for","the","'Get","'","expression","dict","for","a","`","CallbackOutput","`",".","Args",":","name","(","str",")",":","The","name","of","the","callback","output",".","step_name","(","str",")",":","The","name","of","the","step","the","callback","step","associated","with","this","output","belongs","to","."]
code: def _expr(cls, name, step_name):
      """An internal classmethod for the 'Get' expression dict for a `CallbackOutput`.
  
      Args:
          name (str): The name of the callback output.
          step_name (str): The name of the step the callback step associated
              with this output belongs to.
      """
      return {"Get": f"Steps.{step_name}.OutputParameters['{name}']"}
  
imports: from __future__ import absolute_import
  from typing import List, Dict, Union, Optional
  from enum import Enum
  import attr
  from sagemaker.workflow.entities import RequestType
  from sagemaker.workflow.properties import Properties
  from sagemaker.workflow.entities import DefaultEnumMeta
  from sagemaker.workflow.step_collections import StepCollection
  from sagemaker.workflow.steps import Step, StepTypeEnum, CacheConfig
label_desc: Use image node_id 3 for calling the CallbackOutput obj's underlying member method code with example usage: obj._expr(cls, name, step_name) and returns: dict