code: @NonNull
      public Expression in(@NonNull Expression... expressions) {
          if (expressions == null) {
              throw new IllegalArgumentException("expressions cannot be null.");
          }
          final Expression aggr = new AggregateExpression(Arrays.asList(expressions));
          return new BinaryExpression(this, aggr, BinaryExpression.OpType.In);
      }
docs: Create an IN expression that evaluates whether or not the current expression is in the
  given expressions.
  
  @param expressions the expression array to evaluate with.
  @return an IN expression.