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    <p>Use the <code>__bases__</code> attribute:</p> <pre><code>In [68]: class Base(object): ...: # class attribute: ...: class_attr = 0 ...: In [69]: class Derived(Base): ...: @classmethod ...: def inc(cls): ...: p, = cls.__bases__ ...: p.class_attr += 1 ...: In [70]: Base.class_attr Out[70]: 0 In [71]: Derived.inc() In [72]: Derived.inc() In [73]: Base.class_attr Out[73]: 2 </code></pre> <p>If you have multiple inheritance:</p> <pre><code>In [88]: class DifferentInherited(object): ...: class2_attr = 0 ...: In [90]: class Der2(Base, DifferentInherited): ...: @classmethod ...: def inc(cls): ...: print cls.__bases__ ...: a, b, = cls.__bases__ ...: print a.class_attr ...: print b.class2_attr ...: In [91]: Der2.inc() (&lt;class '__main__.Base'&gt;, &lt;class '__main__.DifferentInherited'&gt;) 2 0 </code></pre> <p>Assuming you don't know the inheritance order either, you'll need to test each class for the variable:</p> <pre><code>In [127]: class Der3(DifferentInherited, Base): ...: @classmethod ...: def inc(cls): ...: # This gets a list of *all* classes with the attribute `class_attr` ...: classes = [c for c in cls.__bases__ if 'class_attr' in c.__dict__] ...: for c in classes: ...: c.class_attr += 1 ...: In [128]: Der3.inc() In [129]: Base.class_attr Out[129]: 3 In [131]: DifferentInherited.class2_attr Out[131]: 0 </code></pre> <p>And multiple inheritance uses <code>__mro__</code>:</p> <pre><code>In [146]: class Multi(Der3): ...: @classmethod ...: def inc(cls): ...: c_attr = [c for c in cls.__mro__ if 'class_attr' in c.__dict__] ...: print c_attr ...: c_attr[0].class_attr += 1 ...: In [147]: Multi.inc() [&lt;class '__main__.Base'&gt;] In [148]: Base.class_attr Out[148]: 4 </code></pre>
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    1. PORebinding immutable class attribute in the base class from a derived class
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    1. COThanks, but this has approximately the same level of maintainability as the original with `Base`. What about if I inherit Derived multiply `Derived(AnotherBase, Base)` or across multiple single inheritance `Derived1(Base)`; `Derived(Derived1)`?
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    2. CO`__bases__` and `Base` have nothing in common. `__bases__` refers to the inherited classes. It returns a tuple of classes: `p, = cls.__bases__` gets the first one (The first inherited class - in this case, `Base`.
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    3. COYes I understood your code. What I am saying is that when I have another baseclass named `AnotherBase` and declare a derived class `class Derived (AnotherBase, Base)` then your `p` variable will no more refer to `Base` but to `AnotherBase`. However, `AnotherBase` is not the owner of class attribute `class_attr`. Similarly, with chained inheritance, `p` will refer to `Derived1`, not to `Derived`.
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