code: @NonNull
      @Override
      public Joins join(@NonNull Join... joins) {
          if (joins == null) {
              throw new IllegalArgumentException("joins cannot be null.");
          }
          return new Joins(this, Arrays.asList(joins));
      }
docs: Creates and chains a Joins object for specifying the JOIN clause of the query.
  
  @param joins The Join objects.
  @return The Joins object that represents the JOIN clause of the query.