how to read step count each month from google fit?

Question

I want to read step count data each month from google fit, but the Google fit API is not supported by TimeUnit.YEAR, see:

 new DataReadRequest.Builder()
            .aggregate(DataType.AGGREGATE_STEP_COUNT_DELTA, DataType.AGGREGATE_STEP_COUNT_DELTA)
            .bucketByTime(30,TimeUnit.DAYS)
            .setTimeRange(calendar.getTimeInMillis(),endCalendar.getTimeInMillis() , TimeUnit.MILLISECONDS)
            .build()

I just can get data by each 30 days, not a month. Cause a month maybe have 28,29,30 or 31 days

So is there any way to get it ?