public static Func<TEntity, TProp, TEntity> AsCopyConstructor<TEntity, TProp>(this MethodBase mb, PropertyInfo prop)
{
return _copyCtors.GetOrAdd((mb, typeof(Func<TEntity, TProp, TEntity>), prop),
tpl => mb.CompileCopyConstructor<TEntity, TProp>(prop)) as Func<TEntity, TProp, TEntity>;
}