class_docstr: Checks whether a slot is set at the current step.
  
  The actual `SlotSet` event might have happened at an earlier step.
class_docstr_tok: ["Checks","whether","a","slot","is","set","at","the","current","step",".","The","actual","`","SlotSet","`","event","might","have","happened","at","an","earlier","step","."]
docstr: Returns the tag to be used in a config file.
docstr_tok: ["Returns","the","tag","to","be","used","in","a","config","file","."]
code: def positive_tag() -> Text:
      """Returns the tag to be used in a config file."""
      return "slot_was_set"
  
imports: from rasa.shared.core.domain import Domain
  from typing import Optional, Text, List
  from rasa.core.evaluation.marker_base import OperatorMarker, ConditionMarker, MarkerRegistry, Marker
  from rasa.shared.core.events import ActionExecuted, SlotSet, UserUttered, Event
  import logging
label_desc: Use image node_id 1 for calling the SlotSetMarker obj's underlying member method code with example usage: obj.positive_tag() and returns: str