/// <summary>
/// Create a new specification which is the negation of lhs
/// </summary>
/// <typeparam name="T">Candidate type of specification</typeparam>
/// <returns>New specification negating this one</returns>
/// <returns>New specification representing NOT rhs</returns>
public static ISpecification <T> Not <T>(this ISpecification <T> rhs)
{
if (rhs is TrueSpecification <T> )
{
return(new FalseSpecification <T>());
}
if (rhs is FalseSpecification <T> )
{
return(True <T>());
}
return(NotSpecification <T> .Create(rhs));
}