public DataMutateResult removeGroup(String group) {
        if (!containsGroup(group)) {
            return DataMutateResult.FAIL_LACKS;
        }

        List<String> before = ImmutableList.copyOf(this.groups);
        this.groups.remove(group);
        List<String> after = ImmutableList.copyOf(this.groups);

        this.plugin.getEventDispatcher().dispatchTrackRemoveGroup(this, group, before, after);
        return DataMutateResult.SUCCESS;
    }
Removes a group from this track

@param group the group to remove
@return the result of the operation
common/src/main/java/me/lucko/luckperms/common/model/Track.java