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    <p>I'd recommend using Python's <code>with</code> statement for managing resources that need to be cleaned up. The problem with using an explicit <code>close()</code> statement is that you have to worry about people forgetting to call it at all or forgetting to place it in a <code>finally</code> block to prevent a resource leak when an exception occurs.</p> <p>To use the <code>with</code> statement, create a class with the following methods:</p> <pre><code> def __enter__(self) def __exit__(self, exc_type, exc_value, traceback) </code></pre> <p>In your example above, you'd use </p> <pre><code>class Package: def __init__(self): self.files = [] def __enter__(self): return self # ... def __exit__(self, exc_type, exc_value, traceback): for file in self.files: os.unlink(file) </code></pre> <p>Then, when someone wanted to use your class, they'd do the following:</p> <pre><code>with Package() as package_obj: # use package_obj </code></pre> <p>The variable package_obj will be an instance of type Package (it's the value returned by the <code>__enter__</code> method). Its <code>__exit__</code> method will automatically be called, regardless of whether or not an exception occurs.</p> <p>You could even take this approach a step further. In the example above, someone could still instantiate Package using its constructor without using the <code>with</code> clause. You don't want that to happen. You can fix this by creating a PackageResource class that defines the <code>__enter__</code> and <code>__exit__</code> methods. Then, the Package class would be defined strictly inside the <code>__enter__</code> method and returned. That way, the caller never could instantiate the Package class without using a <code>with</code> statement:</p> <pre><code>class PackageResource: def __enter__(self): class Package: ... self.package_obj = Package() return self.package_obj def __exit__(self, exc_type, exc_value, traceback): self.package_obj.cleanup() </code></pre> <p>You'd use this as follows:</p> <pre><code>with PackageResource() as package_obj: # use package_obj </code></pre>
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    1. POHow do I correctly clean up a Python object?
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    1. USVictor Silva
    1. USClint Miller
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    1. COTechnically speaking, one could call PackageResource().__enter__() explicitly and thus create a Package that would never be finalized... but they'd really have to be trying to break the code. Probably not something to worry about.
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      1. USDavid Z
    2. COBy the way, if you're using Python 2.5, you'll need to do from __future__ import with_statement to be able to use the with statement.
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