class_docstr: Checks that at least one sub-marker applies.
class_docstr_tok: ["Checks","that","at","least","one","sub-marker","applies","."]
docstr: Returns the expected number of sub-markers (if there is any).
docstr_tok: ["Returns","the","expected","number","of","sub-markers","(","if","there","is","any",")","."]
code: def expected_number_of_sub_markers() -> Optional[int]:
      """Returns the expected number of sub-markers (if there is any)."""
      return 1
  
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 2 for calling the NotMarker obj's underlying member method code with example usage: obj.expected_number_of_sub_markers() and returns: int