concise if

PayrollService.kt

fun generatePayrollFor(employeeName: String): Either<Problem, Payroll> {
        return employeeService.findEmployeeByName(employeeName)
            .flatMap { employee ->
                if (employee != null) buildPayrollForEmployee(employee) else UserDoesNotExistProblem(employeeName).left()
            }.tapLeft {
                logger.info("Could not fetch employee: ${it.message()}")
            }
    }