Check if a connection is opened toward a vcenter or an esxi instance

Hi,

For the sake of my scripts, I'd like to check if a connection is already open toward a vcenter or an esxi instance, and if not to call Util::connect() to create a new connection,

Any idea of how to do that?

I know that the MO SessionManager can give info about connections, but as one needs to be connected to access it....

Thanks