public void CreateMapping <TSource, TTarget>()
{
var key = new MappingKey(typeof(TSource), typeof(TTarget));
if (Builders.ContainsKey(key))
{
throw new MappingAlreadyExistsException("Another mapping already exists with the supplied types");
}
var builder = new MappingBuilder <TSource, TTarget>(this);
builder.CreateDefaultBindings();
Builders.Add(key, builder);
BuilderDescriptors.Add(new BuilderDescriptor(typeof(TSource), typeof(TTarget), builder.Dependencies, true));
}