custom event delegate - convertible error

Hi all,

I am using the following:

public event EventHandler<HandCollection> HandsDetected;

with the HandCollection class being:

public class HandCollection
    {
        public ulong TrackingId { get; set; }
        public Hand HandLeft { get; set; }
        public Hand HandRight { get; set; }
    }

but in the console i get the following error and i have no idea why or how to solve it:

"The Type HandCollection must be convertible to ‘Systm.EventArgs’ in order to use it as parameter ‘TEventArgs’ in the generic type or method 'System.EventHandler "

seem to have fixed it, i added:

: System.EventArgs

based on what i read here:

public delegate HandCollection HandCollectionHandler();

 public static event HandCollectionHandler HandDetected;


void Start()
{
HandDetected+=DetectedHand;
}

HandleCollection DetectedHand()
{
return null;
}