docstr: Get the number of transitions in the ER
docstr_tok: ["Get","the","number","of","transitions","in","the","ER"]
code: def num_transitions(self) -> int:
      """
      Get the number of transitions in the ER
      """
      raise NotImplementedError("")
  
imports: from enum import Enum
  from typing import Tuple
  from rl_coach.base_parameters import Parameters
  from rl_coach.memories.backend.memory import MemoryBackend
label_desc: Use image node_id 9 for calling the Memory obj's underlying member method code with example usage: obj.num_transitions() without return types