"Synonyms" of classes
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For the sake of an example I have a `WAV` class which represents WAV sound files. For convenience' sake, I am then required to add a class called `WaveformAudioFile` which has exactly the same functionality.

Regardless of possible design/style issues, what would be an appropriate way to integrate the new class ? By using an extends (with nothing added), by using a common interface or something else ?