assert

A keyword for confirming the truthiness of a given statement that 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

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