text: 
  class Port:
      def __init__(self, mac_address, ip_address, mtu):
          self.mac_address = mac_address
          self.ip_address = ip_address
          self.mtu = mtu
  
      def __str__(self):
          return '(%s - %s - %d)' % (self.mac_address, self.ip_address, self.mtu)
  