kt getUserFromDatabase getOrElse FromNetwork

combineInterfaces.kt

interface DaoOperationsSyntax {
  val dao: DaoDatabase

  fun User.queryUser() = 
    dao.query("SELECT * from Users where userId = ${this.id}")

  fun Company.queryCompany() = 
    dao.query("SELECT * from Companies where companyId = ${this.id}")
}

//We can also combine them together to form new types. Let's create a new NetworkSyntax interface.

interface NetworkSyntax {
  val network: NetworkModule

  fun User.requestUser() = 
    network.request(this.id)
}

//And an interface that's a combination of Network + Dao:

interface RequestSyntax: DaoOperationsSyntax, NetworkSyntax {
  fun User.fetchUser() =
    Try { queryUser() }.getOrElse { requestUser() }
}