Returning Task<bool> from LINQ's Any method?

I have this interface :

public interface ISign
{
   Task<bool> IsRegisteredCopy();
}

Implemented it:

public class Sign : ISign
    {
        TabibContext context = new TabibContext();
        public Task<bool> IsRegisteredCopy()
        {
            return context.Doctors.Any();
        }
    }

So I need to return Task from Any method which is not available!