AppSink methods missing: AttributeError: 'GstAppSink' object has no attribute 'is_eos'

I'm trying to use the AppSink sink to read samples from it but none of the AppSink methods seem to exist on the object.

import gi
gi.require_version("Gst", "1.0")

from gi.repository import Gst
Gst.init()

pipe = Gst.parse_launch("audiotestsrc ! opusenc ! appsink name=sink")
sink = pipe.get_by_name("sink")

while not sink.is_eos():
    pass

Error

Traceback (most recent call last):
  File "x.py", line 9, in <module>
    while not sink.is_eos():
AttributeError: 'GstAppSink' object has no attribute 'is_eos'

gstreamer version:

gst-inspect-1.0 version 1.14.1
GStreamer 1.14.1
https://launchpad.net/distros/ubuntu/+source/gstreamer1.0

from AppSink methods missing: AttributeError: 'GstAppSink' object has no attribute 'is_eos'