purify

library0.3.0pypypi✓ verified 88d ago

A library for creating Pythonic object-mutator transforms as pure functions. Version 0.3.0 supports Python 3.10–3.14. Current release cadence is irregular.

serialization

pip install purify

github ↗package ↗

INSTALL

IMPORT

SIG · PURIFY

purify

serializationpythonv0.3.0

Install

1.6s avg

Import

108ms

Disk

16MB

Pass rate

10/ 10

Env Coverage10 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v0.3.0 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.95 runs

installs and imports cleanly · install 0.0s · import 0.110s · 17.8MB

glibc

py 3.10–3.95 runs

installs and imports cleanly · install 1.6s · import 0.106s · 18MB

16MB installed

● package 16MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

purify

✓ from purify import purify

The main decorator/function is named 'purify'.

Decorate a class with @purify to make all instance methods return new objects instead of mutating the original.

from purify import purify @purify class Person: def __init__(self, name, age): self.name = name self.age = age p = Person('Alice', 30) # Now p.name = 'Alice', p.age = 30 # Under the hood, mutating methods return new instances

Debug

Known issues

breakingPurify 0.3.0 drops support for Python < 3.10. If you are on Python 3.9 or older, pin to <0.3.0.

fix

Upgrade to Python >=3.10 or pin purify<0.3.0.

affects: <0.3.0

gotchaThe @purify decorator only works on classes with a well-defined __init__ that uses simple attribute assignment. Classes with complex initialization or metaclasses may not be supported.

fix

Ensure your class __init__ only sets attributes directly (e.g., self.x = x). Avoid property setters or custom __setattr__.

affects: all

Errors

Common errors & fixes

AttributeError: 'NoneType' object has no attribute 'name'

Calling a mutating method on an instance and expecting the original to change. Because purify returns a new object, the original is unchanged.

fix

Reassign the result: p = p.update_name('Bob') instead of p.update_name('Bob').

TypeError: __init__() should return None, not 'Person'

Attempting to use @purify on a class that already returns a new instance from __init__ or uses a custom __new__. Purify expects __init__ to set attributes only.

fix

Remove any return statements from __init__ and avoid overriding __new__.

ImportError: cannot import name 'purify' from 'purify'

Older versions of purify (pre-0.2.0) had a different module structure. The correct import is 'from purify import purify' (the decorator and the package share the same name).

fix

Use 'from purify import purify' and ensure you have purify >=0.2.0.

Upgrade

Version history

0.3.0latest on PyPI · released Mar 26, 2026

Audit

Dependencies

No dependency data recorded yet.

Agent activity

13 hits · last 30 days

node

Resources

githubhttps://github.com/xoeye/purify ↗

packagehttps://pypi.org/project/purify/ ↗