code: @NonNull
      public Expression between(@NonNull Expression expression1, @NonNull Expression expression2) {
          if (expression1 == null || expression2 == null) {
              throw new IllegalArgumentException("expression1 or expression2 cannot be null.");
          }
          final Expression aggr = new AggregateExpression(Arrays.asList(expression1, expression2));
          return new BinaryExpression(this, aggr, BinaryExpression.OpType.Between);
      }
docs: Create a between expression that evaluates whether or not the current expression is
  between the given expressions inclusively.
  
  @param expression1 the inclusive lower bound expression.
  @param expression2 the inclusive upper bound expression.
  @return a between expression.