python assert with and without parenthesis

Question

Here are four simple invocations of assert:

>>> assert 1==2
Traceback (most recent call last):
  File \"\", line 1, in ?
AssertionError

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Answer 1

The last assert would have given you a warning (SyntaxWarning: assertion is always true, perhaps remove parentheses?) if you ran it through a full interpreter, not through IDLE. Because assert is a keyword and not a function, you are actually passing in a tuple as the first argument and leaving off the second argument.

Recall that non-empty tuples evaluate to True, and since the assertion message is optional, you've essentially called assert True when you wrote assert(1==2, "hi").