Yes, you can absolutely use a string variable instead of a hardcoded string — just make sure you're passing it as a list of strings, not a literal string.

The key is: `labelIds` expects a list, not a string. So you must use square brackets `[]` around the variable, not quotes around a list-shaped string.

Go for:

```python

label_id = 'INBOX'

results = service.users().messages().list(userId='me', labelIds=[label_id]).execute()