public static IJoinableQuery <(TSource1, TSource2)> Join <TSource1, TSource2>(this IJoinableQuery <TSource1> statement, ISource <TSource2> join, Expression <Func <TSource1, TSource2, bool> > on)
{
throw new NotImplementedException();
public static IJoinableQuery <TSource> Join <TSource, TNavigation>(this IJoinableQuery <TSource> statement, Expression <Func <TSource, TNavigation> > expression)
{
throw new NotImplementedException();
}