Python: what is the difference between __str__ and __repr__?

When should I implement __repr__ and when __str__?

• __repr__ is for developers: unambiguous, ideally valid Python that recreates the object. Used by the REPL, repr(), and containers.

• __str__ is for users: readable. Used by print() and str(); falls back to __repr__ if missing.

Always implement __repr__; add __str__ only when a friendlier form helps.