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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 detach(self):
 """ Detaches this volume from any device it may be attached to. If it is not attached, nothing happens. """

        attachments = self.attachments
        if not attachments:
            # Not attached; no error needed, just return
            return
        # A volume can only be attached to one device at a time, but for some
        # reason this is a list instead of a singular value
        att = attachments[0]
        instance_id = att["server_id"]
        attachment_id = att["id"]
        try:
            self._nova_volumes.delete_server_volume(instance_id, attachment_id)
        except Exception as e:
            raise exc.VolumeDetachmentFailed("%s" % e)