Look at this simple example:
s = "ß"
ß is German lowercase double s (The right capitalized form would be ß). The explanation for this happens is that Python doesn't "know" or need to characterize an uppercase conversion for each and every Unicode symbol. So it takes the simple course by assessing s.swapcase() as "SS", so in this manner s.swapcase().swapcase() is "ss".
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