What this snippet does
TypeGuard lies to the static checker; if the runtime logic is wrong, it causes runtime crashes.
Expected output
AttributeError: 'int' object has no attribute 'upper'
Why practise typing this
Typing advanced typing code builds muscle memory for the symbols and indentation Python uses most, which prose-based typing tests never cover. DevType measures your words per minute and accuracy on this snippet and tracks the individual characters you mistype, so later lessons can target them.
More Python practice
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