Couldn't find information on CheckOpened() function

Hi there,
Just wondering what the following function does?
Had an error pop up in our log and couldn't find any documentation on this one on the WinSCP documentation and had a look through: https://winscp.net/eng/docs/library_session
Thanks!

The Session.CheckOpened is an internal method. There's no information on it. It's of no importance to you, as a library user. What actual problem are you facing?