code: def GetForwardedIps(self, interface, interface_ip=None):
      
      try:
        ips = netifaces.ifaddresses(interface)
        ips = ips[netifaces.AF_INET]
      except (ValueError, IndexError):
        return []
      forwarded_ips = []
      for ip in ips:
        if ip['addr'] != interface_ip:
          full_addr = '%s/%d' % (ip['addr'], netaddr.IPAddress(ip['netmask']).netmask_bits())
          forwarded_ips.append(full_addr)
      return self.ParseForwardedIps(forwarded_ips)
docs: Retrieve the list of configured forwarded IP addresses.
  
      Args:
        interface: string, the output device to query.
        interface_ip: string, current interface ip address.
  
      Returns:
        list, the IP address strings.