What does the sdk.getTokensAuthorizationCodeGrant function do?

I am exploring the box node sdk.

and I don't understand what does this function do and return?

https://github.com/box/box-node-sdk#getting-tokens

sdk.getTokensAuthorizationCodeGrant(authCode, null, function(err, tokenInfo) {
	// tokenInfo: {
	//  accessToken: 'ACCESS_TOKEN',
	//  refreshToken: 'REFRESH_TOKEN',
	//  acquiredAtMS: 146***phone number removed for privacy***,
	//  accessTokenTTLMS: 3600000,
	// }
});