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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def save(self, clean=True):
 """Serialize into raw representation. Clears the dirty bit by default. Args: clean (bool):
 Whether to clear the dirty bit. Returns: dict: Raw. """

        ret = {}
        if clean:
            self._dirty = False
        else:
            ret['_dirty'] = self._dirty
        return ret