To the second printing of the first edition:
In the answer to Chapter 4, Question 1, for "'Bacon' < 'Bacon'" read "'Bacon' < 'bacon'".
To the first printing of the first edition, October 2020:
Some unidiomatic uses of == and != for comparisons with None have been replaced by the use of in and not in. This affects the functions found_values and not_none, and Project 2. The textual changes are minimal.
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