<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def ephemeral(cls):
 """ Creates a new ephemeral key constructed using a raw 32-byte string from urandom. Ephemeral keys are used once for each encryption task and are then discarded; they are not intended for long-term or repeat use. """

        private_key = nacl.public.PrivateKey(os.urandom(32))
        return cls(private_key.public_key, private_key)