code: public <P> Q leftJoin(Path<? extends Collection<P>> target, Path<P> alias) {
          getMetadata().addJoin(JoinType.LEFTJOIN, createAlias(target, alias));
          return queryMixin.getSelf();
      }
docs: Define a left join from the Collection typed path to the alias
  
  @param <P> type of expression
  @param target target of the join
  @param alias alias for the join target
  @return current object