teams.py

def get_user_upn(aad_object_id, token):
    response = requests.get(
        f"https://graph.microsoft.com/v1.0/users/{aad_object_id}",
        headers={"Authorization": f"Bearer {token}"},
        timeout=5,
    )
    if response.ok:
        user_data = response.json()
        upn = user_data.get("userPrincipalName") or user_data.get("mail")
        if "@" in upn:
            upn = upn.split("@")[0]
        return upn.lower()
    return "unknown_user_id"