Выводит ошибку "Error:(105, 35) Unresolved reference: builderExpression". Как исправить?

tvEquals.setOnClickListener {
                val text = tvExpression.text.toString()
                val expression = builderExpression(text).build()

                val result = expression.evaluate()
                val longResult = result.toLong()
                if (result == longResult.toDouble()) {
                    tvResult.text = longResult.toString()
                } else {
                    tvResult.text = result.toString()
                }
            }