def identifyUnpaidInvoices()

in src/main/scala/InvoiceHelper.scala [15:18]


  def identifyUnpaidInvoices(invoices: List[Invoice]): String \/ List[Invoice] = {
    val unpaidInvoices = invoices.filter(invoice => invoice.balance > 0)
    if (unpaidInvoices.isEmpty) "Failed to find an unpaid invoice on account".left else unpaidInvoices.right
  }