When removing the DHCP option from an interface address the following error message is given
> vyos@vyos# delete interfaces ethernet eth0 address dhcp
> [edit]
> vyos@vyos# commit
> [ interfaces ethernet eth0 address dhcp ]
> Traceback (most recent call last):
> File "/usr/libexec/vyos/system/normalize-ip", line 32, in <module>
> address_string, prefix_length = re.match(r'(.+)/(.+)', sys.argv[1]).groups()
> AttributeError: 'NoneType' object has no attribute 'groups'
> Stopping DHCP client on eth0 ...