Get Consumer by Username not working?

I’m trying to get a consumer by username.
The documentation says to do /consumers/{username or id}. I seem to be missing something as it’s not working for me.
Kong Version:

➜  ~ kong version
➜  ~ alias csg
 csg='curl -s -X GET'
➜  ~ echo $kad
➜  ~ csg "$kad/consumers" | jq

  "next": null,
  "data": [
      ... a user
      "custom_id": null,
      "created_at": 1558997296,
      "id": "26046496-9286-41bc-9db7-80eca06877a9",
      "tags": null,
      "username": "7e68b45b-6cb9-4420-b364-0281d4859b95"
➜  ~ csg $kad/consumers/7e68b45b-6cb9-4420-b364-0281d4859b95 | jq

  "message": "Not found"

Never mind. I found out that one cannot have UUIDs as username. Perhaps, this could be documented in the Kong docs or prevented when a consumer is created? I could add that to the docs if kong contributors prefer to document it over validation.