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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _check_rf_and_normalize(prefix):
 """ check prefix's route_family and if the address is IPv6 address, return IPv6 route_family and normalized IPv6 address. If the address is IPv4 address, return IPv4 route_family and the prefix itself. """

        addr, masklen = prefix.split('/')
        if ip.valid_ipv6(addr):
            # normalize IPv6 address
            ipv6_prefix = str(netaddr.IPAddress(addr)) + '/' + masklen
            return vrfs.VRF_RF_IPV6, ipv6_prefix
        else:
            return vrfs.VRF_RF_IPV4, prefix