Unknown firecloud model entity type

[jkobject]

when trying to use upload_entities for another entity than participant, sample, sampleset, it never works.

df.index.name = [entityname]_id
upload_entities(entityname, df)

getting

APIException: Sample_group import failed.: (400) : {
  "causes": [],
  "message": "ErrorReport(FireCloud,Unknown firecloud model entity type: sample_group,Some(400 Bad Request),List(),List(),None)",
  "source": "FireCloud",
  "stackTrace": [],
  "statusCode": 400,
  "timestamp": 162462155497

[jkobject]

saving it as tsv and uploading it manually works so it has to be a problem with the API, right?