Call method without payload

[tamazyanarsen]

How to call method without payload? Code from example var add7 = edge.func(function() {/* using System.Threading.Tasks;

public class Startup
{
    public async Task<object> Invoke()
    {
        int v = (int)input;
        return Helper.AddSeven(v);
    }
}

static class Helper
{
    public static int AddSeven(int v) 
    {
        return v + 7;
    }
}

*/});

add7(???, (err, result) => {});