code: func (s *Simulator) Last() *SimulatedInvocation {
  	if len(s.Invocations) == 0 {
  		return nil
  	}
  	return s.Invocations[len(s.Invocations)-1]
  }
docs: ////////////////////////////////////////////////////////////////////////////////
  // Triggering and invocations.
  // Last returns the last invocation in Invocations list or nil if its empty.