Parameter known_face_locations for function face_encodings throwing an error

• face_recognition version:
• Python version:
• Operating System:

Description

I'm trying to limit the area for processing with face_encodings but looks like it's with parameter known_face_locations

What I Did

image = face_recognition.load_image_file(file_name)
face_locations = face_recognition.face_locations(image)
face_encodings = face_recognition.face_encodings(
                file_name,
                known_face_locations=face_locations
            )

as a result i'm getting

  File "/usr/local/lib/python2.7/dist-packages/face_recognition/api.py", line 197, in face_encodings
    raw_landmarks = _raw_face_landmarks(face_image, known_face_locations, model="small")
  File "/usr/local/lib/python2.7/dist-packages/face_recognition/api.py", line 160, in _raw_face_landmarks
    return [pose_predictor(face_image, face_location) for face_location in face_locations]
RuntimeError: Expected writable numpy.ndarray with shape set.

Start in face_recognition/api.py at face_encodings and _raw_face_landmarks, using the reported example to reproduce the RuntimeError. Trace how known_face_locations is passed into the landmark predictor, then add or update a regression test showing that the parameter works without the error.