res = client.functions.schedules.retrieve(id=1)

{
  "items": [
    {
      "id": 4503599627370496,
      "name": "My schedule",
      "createdTime": 1730204346000,
      "cronExpression": "* * * * *",
      "when": "Every hour",
      "sessionId": "<string>",
      "description": "This is a nice schedule",
      "functionId": 4503599627370496,
      "functionExternalId": "my.known.id"
    }
  ]
}