request parameters(timestamp) for client.messages.list and client.monitor.alerts.list

Question

I'm simply fetching data from twilio messages and alerts. But I want to fetch data for specific time range. I noticed that we have parameters:

1. client.messages.list(date_sent_before=xxx, date_sent_after=xxx)
2. client.monitor.alerts.list(start_date=xxx, end_date=xxx)

My question is: Data of those date there is included or excluded?

I did some tests, and it seems below case, can anybody help to confirm?

1.client.messages.list(date_sent_before=xxx, date_sent_after=xxx) data of date_sent_before is excluded while data of date_sent_after is included.

2. client.monitor.alerts.list(start_date=xxx, end_date=xxx) data of start_date and end_date are included.