Import Statuses

When I import a PBIX file, I can get the import status using the route:

https://api.powerbi.com/v1.0/myorg/groups/[org-id]/imports/[import-id]

and it returns something similar to:

{
"id": "[import-id]",
"importState": "Succeeded",
"createdDateTime": "2018-01-24T19:14:31.527Z",
"updatedDateTime": "2018-01-24T19:14:31.527Z",
"name": "[name]",
"connectionType": "import",
"source": "Upload",
"datasets": [],
"reports":[]
}

I would like to know what are the possible values are for "importState", is there a reference list somewhere?