openide/python/python-psi-impl/resources/inspectionDescriptions/PyAbstractClassInspection.html

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<p>Reports invalid definition and usages of abstract classes.</p>
<p><b>Example:</b></p>
<pre><code>
from abc import abstractmethod, ABC


class Figure(ABC):

    @abstractmethod
    def do_figure(self):
        pass


class Triangle(Figure):  # Not all abstract methods are defined in 'Triangle' class
    def do_triangle(self):
        pass


Triangle()  # Cannot instantiate abstract class 'Triangle'
</code></pre>
<p>When the quick-fix is applied, the IDE implements an abstract method for the <code>Triangle</code> class:</p>
<pre><code>
from abc import abstractmethod, ABC


class Figure(ABC):

    @abstractmethod
    def do_figure(self):
        pass


class Triangle(Figure):
    def do_figure(self):
        pass

    def do_triangle(self):
        pass


Triangle()
</code></pre>

It also warns you if <code>abc.abstractmethod</code> is used in a class whose metaclass is not <code>abc.ABCMeta</code>:
<code><pre>
from abc import abstractmethod


class MyClass:
    @abstractmethod  # 'MyClass' is not abstract
    def foo(self):
        ...
</code></pre>
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