add_stream(, rate=float type) causes an error in 13.1.0

[nagadomi]

import av
from fractions import Fraction

container = av.open("output.mp4", 'w')
stream = container.add_stream("libx264", rate=15.0)

Traceback (most recent call last):
  File "/data/nunif-tmp/py_av_bug.py", line 5, in <module>
    stream = container.add_stream("libx264", rate=15.0)
  File "av/container/output.pyx", line 104, in av.container.output.OutputContainer.add_stream
  File "av/utils.pyx", line 51, in av.utils.to_avrational
AttributeError: 'float' object has no attribute 'numerator'

Works fine in 13.0.0 and older.
Is this a new spec or a bug?

[WyattBlue]

This is a consequence of

Permit only setting time_base with a Fraction, as mypy is unable to respect different types in getters vs setters.

because they both use the same utility function. While I think it's okay for PyAV to raise this error (framerate is AVRational, not float64), documentation should have been changed and mypy should be flagging this.

[nagadomi]

Thanks for the answer.
float values like 0.123 have caused errors before, so I don't think it is that major compatibility issue.