Hi team,

While testing the Calendar API using the Python quickstart guide, I noticed an issue in the time formatting line.

The current code is:

now = datetime.datetime.now(tz=datetime.timezone.utc).isoformat() + "Z"  # 'Z' indicates UTC time

However, this results in an invalid ISO 8601 timestamp like:

makefile

2025-04-07T14:39:12.345678+00:00Z

Appending "Z" after a timezone-aware ISO string (which already includes +00:00) makes the timestamp invalid. This can cause unexpected errors when calling the API.

It should be corrected to:

now = datetime.datetime.now(tz=datetime.timezone.utc).isoformat()

When the incorrect format is used, it leads to errors like this:

{
  "error": {
    "code": 403,
    "message": "Method doesn't allow unregistered callers (callers without established identity)...",
    "status": "PERMISSION_DENIED"
  }
}

I've submitted a PR with the fix—please take a look when possible!

Thanks!