def run(situation)
      situation.helper(@name, &definition)
      [:helper]
    end
Calls {Riot::Situation#helper} with the predefined helper name and block at {Riot::Context} run-time.
Though this is like every other kind of {Riot::RunnableBlock}, +run+ will not return a meaningful
state, which means the reporter will likely not report anything.

@param [Riot::Situation] situation the situation for the current {Riot::Context} run
@return [Array<Symbol>] array containing the evaluation state