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

res = client.functions.retrieve(external_id="abc")
res = client.functions.retrieve_multiple(ids=[1, 2, 3])

res = client.functions.retrieve_multiple(external_ids=["func1", "func2"])

{
  "items": [
    {
      "id": 4503599627370496,
      "createdTime": 123455234,
      "status": "Queued",
      "name": "myfunction",
      "fileId": 4503599627370496,
      "externalId": "my.known.id",
      "owner": "user@cognite.com",
      "description": "My fantastic function with advanced ML",
      "metadata": {},
      "secrets": {
        "MySecret": "***"
      },
      "functionPath": "myfunction/handler.py",
      "envVars": {
        "MyKey": "MyValue"
      },
      "cpu": 1,
      "memory": 1.5,
      "runtime": "py313",
      "runtimeVersion": "Python 3.11.10",
      "error": {
        "message": "Function deployment failed.",
        "trace": "ERROR: Could not find a version that satisfies the requirement pandas==99.0.0\nERROR: No matching distribution found for pandas==99.0.0"
      },
      "lastCalled": 1730204346000
    }
  ]
}