GObject.Value fails for GstFraction

$ python3 -c 'from gi.repository import GObject; from gi.repository import Gst; Gst.init([]); from gi.repository import GES; GES.init(); e = GES.Effect.new("aspectratiocrop"); print(1111, e); res, child, pspec = e.lookup_child("GstAspectRatioCrop::aspect-ratio"); print(2222, res, child, pspec, pspec.value_type); res, current = e.get_child_property("GstAspectRatioCrop::aspect-ratio"); print(3333, res, current, type(current)); clone = GObject.Value(pspec.value_type, current); print(4444, clone)'

1111 <GES.Effect object at 0x7efc406e0fc0 (GESEffect at 0x5592f768e740)>
2222 True <__gi__.GstAspectRatioCrop object at 0x7efc406f32d0 (GstAspectRatioCrop at 0x5592f76a9560)> <GstParamFraction 'aspect-ratio'> <GType GstFraction (196)>
3333 True 0/1 <class 'gi.overrides.Gst.Fraction'>
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/usr/lib/python3.7/site-packages/gi/overrides/GObject.py", line 218, in __init__
    self.set_value(py_value)
  File "/usr/lib/python3.7/site-packages/gi/overrides/GObject.py", line 300, in set_value
    raise TypeError("Unknown value type %s" % gtype)
TypeError: Unknown value type <GType GstFraction (196)>