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< h1 > Subclassing Flask< a class = "headerlink" href = "#subclassing-flask" title = "Link to this heading" > ¶< / a > < / h1 >
< p > The < a class = "reference internal" href = "../api.html#flask.Flask" title = "flask.Flask" > < code class = "xref py py-class docutils literal notranslate" > < span class = "pre" > Flask< / span > < / code > < / a > class is designed for subclassing.< / p >
< p > For example, you may want to override how request parameters are handled to preserve their order:< / p >
< div class = "highlight-default notranslate" > < div class = "highlight" > < pre > < span > < / span > < span class = "kn" > from< / span > < span class = "w" > < / span > < span class = "nn" > flask< / span > < span class = "w" > < / span > < span class = "kn" > import< / span > < span class = "n" > Flask< / span > < span class = "p" > ,< / span > < span class = "n" > Request< / span >
< span class = "kn" > from< / span > < span class = "w" > < / span > < span class = "nn" > werkzeug.datastructures< / span > < span class = "w" > < / span > < span class = "kn" > import< / span > < span class = "n" > ImmutableOrderedMultiDict< / span >
< span class = "k" > class< / span > < span class = "w" > < / span > < span class = "nc" > MyRequest< / span > < span class = "p" > (< / span > < span class = "n" > Request< / span > < span class = "p" > ):< / span >
< span class = "w" > < / span > < span class = "sd" > " " " Request subclass to override request parameter storage" " " < / span >
< span class = "n" > parameter_storage_class< / span > < span class = "o" > =< / span > < span class = "n" > ImmutableOrderedMultiDict< / span >
< span class = "k" > class< / span > < span class = "w" > < / span > < span class = "nc" > MyFlask< / span > < span class = "p" > (< / span > < span class = "n" > Flask< / span > < span class = "p" > ):< / span >
< span class = "w" > < / span > < span class = "sd" > " " " Flask subclass using the custom request class" " " < / span >
< span class = "n" > request_class< / span > < span class = "o" > =< / span > < span class = "n" > MyRequest< / span >
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< p > This is the recommended approach for overriding or augmenting Flask’ < / p >
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