def METHOD_NAME(self, provider: Hostingprovider, list_of_networks: List) -> List:
    """
    Return a list of the GreencheckIPs that would be updated
    or created based on the current provided file.
    Return a preview of the networks to import, suitable for displaying
    in a webpage.
    """
    green_ips = []
    green_asns = []
    # try to find a GreenIP
    for network in list_of_networks:
        if self.is_as_number(network):
            # this looks like an AS number
            try:
                as_number = network.split("AS")[1]
                green_asn = GreencheckASN.objects.get(
                    asn=as_number, active=True, hostingprovider=provider
                )
                green_asns.append(green_asn)
            except GreencheckASN.DoesNotExist:
                green_asn = GreencheckASN(
                    active=True, asn=as_number, hostingprovider=provider
                )
                green_asns.append(green_asn)
        if ip_network := self.is_ip_network(network):
            try:
                green_ip = GreencheckIp.objects.get(
                    active=True,
                    ip_start=ip_network[0],
                    ip_end=ip_network[-1],
                    hostingprovider=provider,
                )
                green_ips.append(green_ip)
            except GreencheckIp.DoesNotExist:
                green_ip = GreencheckIp(
                    active=True,
                    ip_start=ip_network[0],
                    ip_end=ip_network[-1],
                    hostingprovider=provider,
                )
                green_ips.append(green_ip)
        if ip_range := self.is_ip_range(network):
            try:
                green_ip = GreencheckIp.objects.get(
                    active=True,
                    hostingprovider=provider,
                    ip_start=ip_range[0],
                    ip_end=ip_range[1],
                )
                green_ips.append(green_ip)
            except GreencheckIp.DoesNotExist:
                green_ip = GreencheckIp(
                    active=True,
                    hostingprovider=provider,
                    ip_start=ip_range[0],
                    ip_end=ip_range[1],
                )
                green_ips.append(green_ip)
    # or make a new one, in memory
    return {"green_ips": green_ips, "green_asns": green_asns}