Item 47, pages 199 & 200: error in code snippet: `data` param value is never assigned to the protected `_data` attribute

[kirisakow]

(2nd ed)

What is written

See code snippet at the bottom of the page 199:

(...) For example, say that I want attribute accesses on my object to actually look up keys in an associated dictionary:

class BrokenDictionaryRecord:
    def __init__(self, data):
        self._data = {}

    def __getattribute__(self, name):
        print(f'* Called __getattribute__({name!r})')
        return self._data[name]

data = BrokenDictionaryRecord({'foo': 3})
data.foo

What is wrong

• Wrong expression in the code snippet at the bottom of the page 199: self._data = {} should be self._data = data, otherwise the data param value is never assigned to the protected _data attribute.

• "Cosmetic" typo: data.foo (the last line) should rather be print('foo: ', data.foo) for the "broken" code snippet to be as close as possible to its "fixed" counterpart.

[bslatkin]

Thank you for the report! Yes it should be self.data = data. I removed the print() part of this to reduce the line noise so it's clear that the error is entirely caused by the attribute access, not trying to stringify the object.

[bslatkin]

Didn't mean to close this :)