Services.scala

import scala.concurrent.Future

case class Department(id: String, name: String, employeeIds: List[String])

case class Employee(id: String, name: String)

case class DepartmentWithEmployees(departmentId: String, departmentName: String, employees: List[Employee])

object DepartmentService {
  def getDepartment(id: String): Future[Option[Department]] = ???
}

object EmployeeService {
  def getEmployee(id: String): Future[Option[Employee]] = ???
}

object DepartmentWithEmployeesService {
  def getDepartmentWithEmployees(departmentId: String): Future[Option[DepartmentWithEmployees]] = {
    // Implement this functionality using the above given functions
  }
}