public function addWhereExpression(WhereExpression $where)
    {
        if (!($this->whereExpression instanceof AndExpression)){
            $this->whereExpression = new AndExpression($this->whereExpression);
        }

        /**
         * @var AndExpression $andExpression
         */
        $andExpression = $this->whereExpression;
        $andExpression->whereExpressions[] = $where;

        return $andExpression;
    }