code: def handle(cls, value, provider=None, **kwargs):
          
  
          if provider is None:
              raise ValueError('Provider is required')
  
          d = deconstruct(value)
          stack_fqn = d.stack_name
          output = provider.get_output(stack_fqn, d.output_name)
          return output
docs: Fetch an output from the designated stack.
  
          Args:
              value (str): string with the following format:
                  <stack_name>::<output_name>, ie. some-stack::SomeOutput
              provider (:class:`stacker.provider.base.BaseProvider`): subclass of
                  the base provider
  
          Returns:
              str: output from the specified stack