Spotify access token method using get token is expired in 1 hour?

[rahulinfibrain]

I have implementation spotify_sdk: ^3.0.2 using in our project.
I have not idea getAccessToken method using get access token it's expired on 1 hour?
I have confused your package not any doc provide access token is expired in 1 hour but spotify official doc says
"Access token is valid for 1 hour".

https://developer.spotify.com/documentation/web-api/concepts/access-token

please suggestion which is correct.