To reproduce:
```
set protocols bgp 100 peer-group foo remote-as 200
set protocols bgp 100 peer-group bar-baz remote-as 201
set protocols bgp 100 peer-group bar_baz remote-as 201
set protocols bgp 100 neighbor 192.0.2.1 peer-group foo
set protocols bgp 100 neighbor 192.0.2.2 peer-group bar-baz
set protocols bgp 100 neighbor 192.0.2.3 peer-group bar_baz
commit
[ protocols bgp 100 neighbor 192.0.2.2 peer-group bar-baz ]
protocols bgp 100 peer-group bar-baz doesn't exist
[[protocols bgp 100]] failed
Commit failed
```
FRR allows a peer-group to contain a hyphen
```
router bgp 100
neighbor foo-bar peer-group
neighbor foo-bar remote-as 200
neighbor 1.1.1.1 peer-group foo-bar
!
```