Published Apr 12, 2022Updated Sep 22, 2023
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The assert keyword confirms the truthiness of a given statement and is often used to facilitate development, document code, and debug.


assert some_condition, assert_message

The assert keyword is followed by some_condition to be tested, such as validating a data type or membership within a given container. An optional assert_message can be added that will be printed when the assertion error is raised.


The assert keyword can be used to validate a value (or evaluate some other condition):

fav_color = 'blue'
assert fav_color == 'red'
# Output: AssertionError

Codebyte Example

The following example uses assert to evaluate if 'mud' is within the following list things_that_float:


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