code: func (step *CallFlowSayStep) MarshalJSON() ([]byte, error) {
  	data := jsonCallFlowSayStep{}
  	data.CallFlowStepBase = step.CallFlowStepBase
  	data.Action = "say"
  	data.Options.Payload = step.Payload
  	data.Options.Voice = step.Voice
  	data.Options.Language = step.Language
  	data.Options.Repeat = step.Repeat
  	data.Options.IfMachine = step.IfMachine
  	data.Options.MachineTimeout = int(step.MachineTimeout / time.Millisecond)
  	return json.Marshal(data)
  }
docs: // MarshalJSON implements the json.Marshaler interface.