if hook is defined in config twice then all operations are made 2 times

if in config there is:

{
    "library": "/usr/local/lib/hooks/libdhcp_class_cmds.so"
}, {
    "library": "/usr/local/lib/hooks/libdhcp_class_cmds.so"
}

then operations like 'class-add' are performed 2 times. In case of 'class-add' the second one fails as there is already given class present.

UPDATE: See the discussion below. This is uncommon, but valid. However, Kea should print a warning if the same hook is loaded more than once.