The output contains SOURCE IS UNAVAILABLE？

[Prague2049]

After the format of py file is formatted by python-black，the output not contain the code of the original program.
As follow:
18:41:59.34 ...... self = <main.Solution object at 0x11f297460>
18:41:59.34 ...... nums = [2, 0, 2, 1, 1, 0]
18:41:59.34 ...... len(nums) = 6
18:41:59.34 27 | SOURCE IS UNAVAILABLE
18:41:59.34 29 | SOURCE IS UNAVAILABLE
18:41:59.34 ...... n = 6
18:41:59.34 32 | SOURCE IS UNAVAILABLE
18:41:59.34 ...... p = (6,)
18:41:59.34 ...... len(p) = 1
18:41:59.34 33 | SOURCE IS UNAVAILABLE
18:41:59.34 ...... res = []
18:41:59.34 34 | SOURCE IS UNAVAILABLE
18:41:59.36 ...... j = 0
18:41:59.36 35 | SOURCE IS UNAVAILABLE

[alexmojaki]

Can you share example code that reproduces this? It sounds like maybe the file was reformatted while it was running.