[Python] brython in iframe nags about:srcdoc#__main__ is not a url

I'm resctircted to use iframe

<html style='height: 100%'>
<head>
<script src='https://cdn.jsdelivr.net/npm/brython@3/brython.min.js'></script>
<script src='https://cdn.jsdelivr.net/npm/brython@3/brython_stdlib.js'></script>
</head>
<body>
<div>
<canvas id='my_canvas' > </canvas>
<script>
__BRYTHON__.brython_path =
'https://cdn.jsdelivr.net/npm/brython@3/brython.min.js'
__BRYTHON__.script_path =
'https://cdn.jsdelivr.net/npm/brython@3/brython.min.js'
console.log('asd', __BRYTHON__.script_path )
</script>
<script type='text/python3'>
from browser import document, html , timer

time_elapsed = 0
canvas = document["my_canvas"]
ctx = canvas.getContext("2d")

def draw_circle(t):
ctx.clearRect(0, 0, canvas.width, canvas.height)
radius = 50 + 30 * math.sin(t / 10)
ctx.beginPath()
ctx.arc(150, 150, radius, 0, 2 * math.pi)
ctx.stroke()

timer.set_interval(lambda: draw_circle(timer.time_elapsed() ), 50)

</script>
</div>
</body>
</html>


and I get :

Uncaught Error: not a url: about:srcdoc#__main__
at $B.strip_host (brython.min.js:1:2062)
at run_scripts (brython.min.js:1:58001)
at $B.parser.brython (brython.min.js:1:55126)
at ev.target.body.onload (brython.min.js:1:52395)

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