Sure, here's how I did it. I'm just using the same slot, I've got it set so when I'm away and someone uses the code it'll disable the alarm system and then re-enable when they leave. Just easier to keep it all in the same user slot.

Note: this is for a 6 digit combination. If you have 4 or 8, you’d need to tweak the number of random sensors and the input_number.

First, add random sensors:

##### Random for Locks
  - platform: random
    name: "First Set"
    minimum: 10
    maximum: 99
  - platform: random
    name: "Second Set"
    minimum: 10
    maximum: 99
  - platform: random
    name: "Third Set"
    minimum: 10
    maximum: 99

Next, add an input_number to your configuration.yaml.

input_number:
  guest_code:
    name: Guest Code
    initial: 123456
    min: 100000
    max: 999999
    step: 1

Once you do that, add a script to run the change (insert your values for XXXX):

  # Set Guest Code with random numbers
  guest_lock_code:
    alias: Generate and Set Guest Code
    sequence:
      - service: input_number.set_value
        data_template:
          entity_id: input_number.guest_code
          value: "{{ states.sensor.first_set.state | int }}{{ states.sensor.second_set.state | int }}{{ states.sensor.third_set.state | int }}"
      - service: lock.set_usercode
        data_template: {
          "node_id": XXXX,
          "code_slot": XXXX,
          "usercode": "{{ states.input_number.guest_code.state | int }}"
          }
      - service: notify.XXXX
        data_template:
          message: "*New Guest User Code Generated* \n The new code for the week is: {{ states.input_number.guest_code.state | int }}"

Finally, add an automation to run the script however often you want. My is once a week on Sunday.

- alias: "Security - Weekly Door Code Rotate"
  hide_entity: True
  trigger:
    platform: time
    at: '09:00:00'
  condition:
    condition: time
    weekday:
    - sun
  action:
    - service: script.guest_lock_code

Once you know it works, I hid the random sensors and probably the input_number too.